Genetics and Eugenics in Frank Herbert’s Dune-verse

Discussion of fictional eugenics program in the SF Dune-verse and how it contradicts contemporary known human genetics but suggests heavy agricultural science and Mendelian inspiration to Frank Herbert’s worldview.
criticism, transhumanism, genetics, SF, insight-porn
2018-05-052019-01-12 finished certainty: highly likely importance: 3


Frank Her­bert’s SF Dune se­ries fea­tures as a cen­tral me­chanic a mul­ti­-mil­len­nium hu­man eu­gen­ics breed­ing pro­gram by the Bene Gesser­it, which pro­duces the main char­ac­ter, Paul Atrei­des, with pre­cog­ni­tive pow­ers. The breed­ing pro­gram is de­scribed as oddly slow and in­effec­tive and re­quir­ing roles for in­cest and in­breed­ing at some points, which con­tra­dict most pro­posed hu­man eu­gen­ics meth­ods. I de­scribe the two main his­tor­i­cal par­a­digms of com­plex trait ge­net­ics, the Fish­er­ian in­fin­i­tes­i­mal model and the Mendelian mono­genic mod­el, the for­mer of which is heav­ily used in hu­man be­hav­ioral ge­net­ics and the lat­ter of which is heav­ily used in agri­cul­tural breed­ing for novel traits, and ar­gue that Her­bert (in­cor­rectly but un­der­stand­ably) be­lieved the lat­ter ap­plied to most hu­man traits, per­haps re­lated to his long­stand­ing au­to­di­dac­tic in­ter­est in plants & in­sects & farm­ing, and this un­stated but im­plicit in­tel­lec­tual back­ground shaped Dune and re­solves the anom­alies.

One of the odder things in the 1965 SF novel , among its many ex­u­ber­ant ideas, is the role of ge­net­ics. Genes are con­stantly be­ing in­voked as a cen­tral the­me, cause, and goal, mold­ing and be­ing molded by all main char­ac­ters, but to a reader fa­mil­iar with hu­man ge­net­ics, es­pe­cially mod­ern mol­e­c­u­lar ge­net­ics, or his­tor­i­cal eu­gen­ics, the role of genes makes no sense.

This is odd be­cause (1920–1986), while defi­nitely a soft SF au­thor who will never be mis­taken for , was nev­er­the­less a wide­ly-read au­to­di­dact and great en­thu­si­ast for sci­ence and tech­nol­o­gy, turn­ing his farm home into a demon­stra­tion project for fuel effi­ciency & home au­toma­tion among other things, and writ­ing a home com­puter man­ual (With­out Me You’re Noth­ing: The Es­sen­tial Guide to Home Com­put­ers, 1980). Dune fa­mously be­gan in a mag­a­zine ar­ti­cle on eco­log­i­cal re­search in Ore­gon on dune recla­ma­tion, and Her­bert did ex­ten­sive back­ground re­search to de­velop the world—eg he says “I did a year at the Li­brary of Con­gress. I did about six years on the whole book (Dune). I leaned on Mus­lim and Arab his­tory very heav­i­ly. I did an ex­ten­sive study of Arab his­to­ry. I also used the Li­brary of the British Mu­se­um. I’ve lived in the desert. I was do­ing other things dur­ing those six years. Don’t get the idea that was all I did. But I did the re­search over a six-year pe­riod (from 1959 to 1965).”, which in­cludes ob­scure his­tor­i­cal episodes like the Cau­ca­sus re­sis­tance to Russ­ian im­pe­ri­al­ism. The Bene Gesserit phi­los­o­phy draws on , the Men­tats are based on id­iot sa­vants, the still­suits are high­-tech Bedouin robes, the are old ideas for pow­ered flight, the melange spice bears many re­sem­blances to psy­che­delics like LSD, the an­ces­tral mem­ory re­calls Jung’s spec­u­la­tions about a & west­ern oc­cul­tic “”, “Dune Tarot” is based on Tarot, the “” ac­ci­den­tally wound up hav­ing not one but two ref­er­ences (to Her­bert’s an­ti-de­vel­op­ment ac­tivist friend & to of )—even the bizarre speech by Leto II in with the com­par­i­son of war to or­gasms as jus­ti­fi­ca­tion for Leto II’s al­l-fe­male army had a ba­sis (Her­bert cites the ob­scure book The Sex­ual Cy­cle of Hu­man War­fare, Wal­ter 19501). Her­bert’s use of ge­net­ics in Dune is also far from a one-off, as themes of se­lec­tive breed­ing/­cloning/­ge­netic en­gi­neer­ing show up in many of his other SF books as well, like or or or or or (for dis­cus­sions of them, a good source is Touponce 1988, Frank Her­bert). So where does the al­l-per­va­sive role of ge­net­ics come from, even if only loose­ly? It cer­tainly does­n’t come from a stan­dard be­hav­ioral ge­net­ics text­book or from stan­dard re­search find­ings on the ge­net­ics of in­tel­li­gence (the sort of topic which one might ex­pect to in­spire a fic­tional eu­gen­ics breed­ing pro­gram for in­tel­li­gence and ESP).

The Bene Gesserit breeding program

‘“Ever sift sand through a screen?” she asked…“We Bene Gesserit sift peo­ple to find the hu­mans.”’

RM Gaius He­len Mo­hi­am, Dune

“Grow up, hu­man­s!…That’s their [the BG’s] dream. Start act­ing like adults and not like an­gry chil­dren in a school­yard.”

RM Murbel­la,

“I think we are the best equipped sur­vival an­i­mal that this planet has ever pro­duced. I don’t de­pend just on ra­tio­nal­i­ty, I de­pend on the need to sur­vive, on the urge to sur­vive, on the de­sire to sur­vive as a species. This is be­hind a lot of what I write. It pleases me to think that 20,000 years in the fu­ture, 20 mil­lion years in the fu­ture, there will be hu­man be­ings around en­joy­ing life the way I en­joy life.”

Frank Her­bert, part 5 of his 1983 pre- in­ter­view

To sum­ma­rize the ge­net­ics and breed­ing pro­gram as de­scribed in the Dune se­ries: for thou­sands of years (in­deed, “across thou­sands of gen­er­a­tions”), stem­ming from, Her­bert im­plies in com­ments2, Amer­i­can and the USSR ‘New So­viet Man’ ori­gins, the sis­ter­hood has been run­ning a per­sis­tent highly or­ga­nized breed­ing pro­gram fo­cused on the sis­ter­hood’s mem­bers and the Great Houses of the hu­man Em­pire, us­ing arranged mar­riages and po­lit­i­cal sub­terfuge as nec­es­sary to cre­ate the de­sired cross­ings in the over­all pedi­gree, aimed at in­creased in­tel­li­gence, mo­tor skill, so­cial skills & ma­nip­u­la­tion, self­-dis­ci­pline, and most of all, the cre­ation of the ‘’, a man ca­pa­ble of highly pow­er­ful long-range ac­cu­rate pre­cog­ni­tive ESP of the fu­ture and also ac­cess­ing the ‘an­ces­tral mem­o­ries’ (the life­long mem­o­ries of all their fore­bears) of both their male & fe­male lin­eage with­out los­ing their san­ity or be­ing ‘pos­sessed’ by an­ces­tral per­son­al­i­ties.3 Pre­cog­ni­tion is al­ready pos­si­ble to a lim­ited ex­tent, and the fe­male half of the an­ces­tral mem­o­ries are avail­able to the most elite Bene Gesserit (the ‘Rev­erend Moth­ers’), but the KH ap­par­ently would pos­sess it in far greater de­gree. It is un­clear to what ex­tent these are due to the pre­vi­ous suc­cesses of the breed­ing pro­gram. All of these traits are nec­es­sary to cre­ate a hu­man­ity which in­creases its ca­pa­bil­i­ties with­out lim­it, grow­ing into its ‘adult­hood’, and be­com­ing ca­pa­ble of long-term plan­ning and sur­vival in an open-ended uni­verse with­out any cer­tain­ties or hard rules, with­out falling into crutches like the de­struc­tive “hero myth” and mak­ing true democ­racy a pos­si­bil­ity4. (This em­pha­sis on self­-mas­tery and in­creased ca­pa­bil­i­ties lead­ing to lib­er­a­tion Sec­ond Apoc­a­lypse fan­tasy se­ries, which draws heav­ily on Her­bert, but where self­-mas­tery of psy­chol­ogy & bi­ol­ogy ul­ti­mately leads not to hu­man flour­ish­ing but to ni­hilism, he­do­nism, damna­tion, war against the gods, and death.)

The BG de­cline to use tech­no­log­i­cal meth­ods like AI or ge­netic en­gi­neer­ing in their breed­ing pro­gram. Shortly be­fore Dune, the BG be­lieve that they are fi­nally within a gen­er­a­tion or two of suc­cess, and plan a fi­nal cross: , daugh­ter of , will have a daugh­ter with Duke Leto I Atrei­des, and the daugh­ter will then be with Baron Harkon­nen’s nephew, , and this rather in­bred & in­ces­tu­ous grand­son will likely be the KH. Jes­si­ca, how­ev­er, has a son (), who un­ex­pect­edly be­comes the KH and leads a re­bel­lion against the Harkon­nen, be­ing pit­ted against Fey­d-Rautha & Baron Harkon­nen, both of whom are killed. In re­sponse to the im­pend­ing dis­as­ter, the BG “pre­serve the [Harkon­nen] blood­line” by a last-ditch mat­ing of a BG sis­ter () with Fey­d-Rautha, and count on Lady Jes­si­ca’s sec­ond child, a daugh­ter (), to the other half.

In , it is re­vealed the Bene Gesserit have a coun­ter­part, the , who spe­cial­ize in bi­o­log­i­cal and ge­netic en­gi­neer­ing (e­spe­cially cloning); they ca­su­ally re­veal that they have “dab­bled in var­i­ous pure essences”, in­clud­ing a KH of their own, to study nat­ural ex­tremes (“na­ture often pro­duces cre­ations as deadly as ours”) in sci­en­tific con­di­tions but they found him un­con­trol­lable & he com­mit­ted sui­cide. In , Paul Atrei­des’s two fra­ter­nal twins, and , are at the cen­ter of po­lit­i­cal in­trigue in the now-head­less Em­pire, and both of them are po­ten­tial KHs, dri­ving the BG to des­per­ate moves to re­trieve their genes some­how, with their pre­ferred so­lu­tion be­ing a broth­er-sis­ter mat­ing5, to lock in the KH genes into an off­spring de­spite the po­lit­i­cal scan­dal and ab­solute con­dem­na­tion of their tra­di­tional Fre­men sup­port­ers, and the risk of re­ces­sive genes com­pli­cat­ing it. They re­ject that op­tion, and Leto II in­stead merges him­self with the sand­worms to be­come a nigh-im­mor­tal wor­m-hu­man hy­brid, Alia ul­ti­mately is dri­ven in­sane and com­mits sui­cide, and the BG breed­ing pro­gram is taken over by the trans­formed God-Em­peror Leto II. In , Leto II takes over the BG breed­ing pro­gram6 for ad­di­tional mil­len­nia as part of his grand plan to en­sure the per­ma­nent sur­vival of the hu­man race against the pos­si­bil­ity of pre­scient ma­chi­nes/ar­ti­fi­cial in­tel­li­gences be­ing de­vel­oped & turn­ing against hu­man­i­ty; the Golden Path breed­ing pro­gram con­tin­ues un­til the birth of a very dis­tant Atrei­des de­scen­dant, Siona, who is in­vis­i­ble to pre­science (a bi­o­log­i­cal ver­sion of “no-ships”/”, so per­haps one should dub Siona as hav­ing a ‘no-gene’). By this point the breed­ing pro­gram has suc­cess­fully de­vel­oped hu­mans to the ex­tent that the last ghola of Dun­can Ida­ho, famed mar­tial artist, can be de­feated by even an old man;7 and by the end of the se­ries, be­ing a Men­tat, an achieve­ment of only the most in­tel­li­gent & well-trained in Dune and some­thing re­mark­able in Paul Atrei­des, has be­come com­mon­place (and the fi­nal mys­te­ri­ous en­emy scoffs at Men­tats–“Dime a dozen, they are.”) Sion­a’s ac­tions pre­cip­i­tate the death of Leto II, the col­lapse of the hu­man Em­pire, and the ex­o­dus of count­less bil­lions of hu­mans in a di­as­pora across the mul­ti­verse where they will adapt and evolve to lo­cal con­di­tions and change in un­pre­dictable ways with the de­vel­op­ment of brand new genes. (“Think of the un­counted genes out there! Think of the po­ten­tial tal­ents float­ing free in uni­verses where they might be lost forever!”)

The re­main­ing 2 books (, ) deal with ge­net­ics mostly in the form of “” clones, only some­what touch­ing on the ‘un­counted genes’ man­i­fested in new kinds of hu­man ca­pa­bil­i­ties like the “fu­tars” & “Hon­ored Ma­tres”; the fi­nal book, Chap­ter­house: Dune, ends with the pro­tag­o­nists es­cap­ing from a mys­te­ri­ous en­emy (who ap­pears in the guise of kindly old ‘farm­ers’ on a farm dis­cussing how to best breed their crops) along with the last Bene Tleilax who is car­ry­ing an archive of cells taken from all the ma­jor char­ac­ters of the se­ries. It is im­plied that they will all be cloned as gho­las, with their mul­ti­far­i­ous tal­ents pre­served in­tact, to be used in the con­tin­ued de­vel­op­ment of hu­man­ity to­wards the goal of adult­hood.

(The Brian Her­bert/Kevin J. An­der­son nov­els ap­par­ently go into con­sid­er­able de­tail about the ori­gins of the BG and goals, based on the ever-ex­pand­ing se­cret ma­te­r­ial Frank Her­bert left be­hind, but as there is no cred­i­ble third-party ev­i­dence that they are draw­ing on au­then­tic ma­te­ri­al, and their nov­els are too lousy to read, I will ig­nore them here al­though it’s pos­si­ble at least their se­quels to Chap­ter­house: Dune, /, are based on some de­gree of au­then­tic ma­te­r­ial which could be re­verse-engi­neered with suffi­ciently care­ful read­ing.8 It would also be worth re­mark­ing on Des­ti­na­tion: Void’s use of clones, but I don’t re­call it suffi­ciently well, and I haven’t read yet.)

A human/animal genetics evaluation

To quickly sum­ma­rize some rel­e­vant hu­man & an­i­mal ge­net­ics: the be­hav­ioral ge­net­ics par­a­digm traces back to the British “bio­met­ric” school of ge­net­ics which be­gan with & dis­cussing kinds of “blend­ing in­her­i­tance” for the very grad­ual process of evo­lu­tion, lead­ing to sub­tle changes com­pound­ing for eons, which Dar­win set out in Ori­gin of Species; Gal­ton’s in­ves­ti­ga­tions ul­ti­mately led to the cen­tral role of the and and and in math­e­mat­i­cally mod­el­ing the in­her­i­tance of con­tin­u­ous traits like height, which even­tu­ally was per­fected by in­fin­i­tes­i­mal mod­el, where the con­ti­nu­ity of traits like height (as op­posed to sim­ple dis­crete Mendelian traits which shift be­tween differ­ent phe­no­types un­der the in­flu­ence of one or a few genes) is due to the trait be­ing caused by the sim­ple ad­di­tive sum of the av­er­age effect from thou­sands or tens of thou­sands of ge­netic vari­ants. This could even ac­count for the count­less bi­nary or dis­crete traits which clearly had ge­netic in­flu­ence and ran in fam­i­lies but failed to fol­low any kind of Mendelian pat­tern what­so­ev­er, such as al­co­holism or schiz­o­phre­nia, by the where a thresh­old is de­fined and the phe­no­type man­i­fests if the sum of all ge­net­ics vari­ants & en­vi­ron­men­tal in­flu­ences (a nor­mal­ly-dis­trib­uted vari­able) passes a cer­tain crit­i­cal to­tal. This par­a­digm matches data from twin stud­ies, adop­tion stud­ies, pedi­gree and fam­ily stud­ies, and has en­joyed im­mense suc­cess in re­cent decades with the ad­vent of genome se­quenc­ing. (And we could also use it to ex­plain other fic­tional ge­netic sce­nar­ios, like 9 or the 3 pony races in .10) In­tel­li­gence/IQ in par­tic­u­lar fits this par­a­digm well and the con­sen­sus is that it is highly poly­genic, ad­di­tive, much of the rel­e­vant ge­netic vari­ants are com­mon ones, and while rare vari­ants & de novo mu­ta­tions are usu­ally re­spon­si­ble for cases of se­vere re­tar­da­tion, most be­low-av­er­age in­tel­li­gence is sim­ply the lower end of a con­tin­u­um, and there are few or no rare vari­ants which cause ex­tremely high in­tel­li­gence or which offer a large boost in in­tel­li­gence.

Given this, the breed­ing pro­gram in Dune makes no sense. (For a good re­view of quan­ti­ta­tive ge­net­ics an­i­mal breed­ing meth­ods, see , Gi­anola & Rosa 2015; for what Frank Her­bert would’ve had ac­cess to at the time, see the dean of Amer­i­can an­i­mal breed­ing, enor­mously in­flu­en­tial text­book, An­i­mal Breed­ing Plans.)

A con­tin­u­ous poly­genic trait re­sponds quickly to se­lec­tion, and in dis­cussing eu­gen­ics, even the most pes­simistic es­ti­mates by R.A. Fisher of how many gen­er­a­tions it might take to dras­ti­cally in­crease av­er­age hu­man in­tel­li­gence or al­most en­tirely elim­i­nate a nasty re­ces­sive might be 20 gen­er­a­tions—cer­tainly not “thou­sands of gen­er­a­tions”. This would hold true of other traits one might se­lect for, and se­lect­ing for many traits si­mul­ta­ne­ously would in­crease the num­ber of gen­er­a­tions rel­a­tively mod­est­ly. Since there are few or no rare vari­ants fos­ter­ing ex­tremely high in­tel­li­gence or other de­sir­able traits, all of the nec­es­sary vari­ants ex­ist al­ready in the hu­man gene pool and merely need to be in­creased or de­creased in fre­quen­cy, which can be done rapidly with­out wait­ing cen­turies (or tens of mil­len­nia) for “hope­ful mu­tants”. Due to the CLT, for a highly poly­genic ad­di­tive trait, the start­ing pop­u­la­tion mean may be ex­tremely dis­tant from the end re­sult of a se­lec­tive breed­ing pro­gram (no will ever have a puppy as big as the av­er­age ), so it would be in­cor­rect for the Bene Tleilax to claim that the base­line hu­man pop­u­la­tion could oc­ca­sion­ally throw up ex­tremes any­where as ex­treme as their ul­ti­mate ‘essences’.

If any­one did such a pro­gram, it would be self­-de­feat­ing to re­strict the pro­gram to a few aris­to­crats be­cause the fam­i­lies would regress to the mean and would be con­stantly di­luted by in­ter­mar­riage from the gen­eral pop­u­la­tion (e­spe­cially over mil­len­nia) and such a re­stric­tion risks var­i­ous ills from a small effec­tive pop­u­la­tion as it greatly in­creases the risk of bad luck and ex­ag­ger­ates the effects of ; it would be best to do it on as egal­i­tar­ian a ba­sis as pos­si­ble, and if it has to be lim­ited to a cer­tain size, se­lect any­one with high trait val­ues with lit­tle re­gard for lin­eage.

Should a high ge­netic level be reached and main­tained, it would then not be es­pe­cially im­por­tant to mate this per­son with that per­son, since it is only the av­er­age which mat­ters, and a mi­s­aimed mar­riage sim­ply means a slight re­duc­tion in se­lec­tion effi­cien­cy; nor would there be any­thing par­tic­u­larly spe­cial about a broth­er-sis­ter in­breed­ing, other than in­cur­ring & an in­creased risk of birth de­fect­s/­ge­netic dis­eases (which is not good but tol­er­a­ble as long as it is not re­peat­ed, in some eras such a mat­ing was quite com­mon, and even now is com­mon & pre­ferred in many so­ci­eties). Like­wise, it would not be ter­ri­bly im­por­tant to carry the ex­act cells of par­tic­u­lar noted fig­ures to clone them rather than, say, a sib­ling or sev­eral more dis­tant rel­a­tives.

Alternative paradigms

So is it all just non­sense?

Well, there is an al­ter­na­tive par­a­digm of ge­net­ics, which may be more fa­mil­iar to most read­ers: the , trace­able to and his peas, but taken up with great en­thu­si­asm by Amer­i­cans. In Mendelian ge­net­ics, the fo­cus is over­whelm­ingly on sin­gle ge­netic vari­ants with large effects, which since they come in pairs can have sim­ple ad­di­tive dose-re­sponse effects (0/1/2 copies), non-ad­di­tive effects such as (one copy is enough to cause the trait), “re­ces­sive” (two copies are re­quired), and lead to com­pli­cated in­her­i­tance pat­terns where a trait may dis­ap­pear but then pop up many gen­er­a­tions lat­er, or where sev­eral ge­netic vari­ants may only have a par­tic­u­lar effect when all of them are present si­mul­ta­ne­ously (“”). Mendelian ge­net­ics ap­plies well to a num­ber of rare hu­man dis­eases, and a few odd­ball traits, but works par­tic­u­larly well in agri­cul­tural and sci­en­tific set­tings, where it can be demon­strated vividly and used to track mu­ta­tions and in­ves­ti­gate their effects, among many other things. The de­vel­op­ment of Mendelian ge­net­ics thus lead to a no­to­ri­ously bit­ter aca­d­e­mic dis­pute be­tween the bio­me­tri­cians and the Mendelians, be­cause nei­ther side was wrong: there clearly were Mendelian traits which were busily be­ing ex­per­i­men­tally demon­strated in plants and flies and mice, but it was also clear that Mendelian ap­proaches could­n’t ac­count for traits like height. (For more back­ground, see Provine’s The Ori­gins of The­o­ret­i­cal Pop­u­la­tion Ge­net­ics, Gilham’s A Life of Sir Fran­cis Gal­ton, and Paul & Spencer 1995.) The feud was only par­tially re­solved by R.A. Fish­er’s fa­mous uni­fi­ca­tion demon­strat­ing that the con­tin­u­ous traits could be seen as sim­ply the sum of in­defi­nitely many ge­netic vari­ants each of which acted in a Mendelian man­ner. (In par­tic­u­lar, Mendelian­ism was avidly adopted by Amer­i­can eu­geni­cists, who pro­ceeded to in­ter­pret traits like low in­tel­li­gence or al­co­holism or schiz­o­phre­nia as be­ing sin­gle Mendelian ge­netic vari­ants, often re­ces­sive, rather than be­ing part of a con­tin­uum in which suffer­ers merely have bad luck and some­what lower av­er­age num­ber of fa­vor­able vari­ants. While un­der a bio­met­rics par­a­digm, it would be about equally effec­tive to try to in­crease in­tel­li­gence by in­creas­ing the fer­til­ity of more in­tel­li­gent peo­ple ver­sus de­creas­ing the fer­til­ity of lower in­tel­li­gence, un­der Amer­i­can Mendelian­ism run amok, all low in­tel­li­gence/­men­tal ill­ness/dis­ease ‘must’ be due to re­ces­sives as proven by slop­py, bi­ased—or per­haps even fal­si­fied—­pedi­gree charts of ar­bi­trar­ily di­chotomized traits, and as in­creas­ing the fer­til­ity of high­-trait peo­ple is largely fu­tile then, in the ab­sence of any kind of ge­netic test­ing co­er­cive gov­ern­men­t-backed ster­il­iza­tion ap­proaches then be­come the nat­ural ap­proach—e­spe­cially for the strong lib­eral pro­gres­sive tra­di­tion in Amer­ica which was an ad­vo­cate of gov­ern­ment in­ter­ven­tion to re­shape so­ci­ety eg Pro­hi­bi­tion or min­i­mum wage.)

The Mendelian mono­genic par­a­digm, with heavy em­pha­sis on var­i­ous non­lin­ear or in­ter­ac­tion rather than sim­ple ad­di­tive effects, re­mains highly in­flu­en­tial in sci­en­tific re­search. (In­deed, per­haps far more than it should. It seems to me that the dis­ap­pointed hopes of rapidly find­ing most dis­ease-caus­ing ge­netic vari­ants after the Hu­man Genome Project rested on qua­si­-Mendelian be­liefs and dis­re­gard­ing the ev­i­dence of high ad­di­tive & poly­genic­ity of most hu­man traits in­clud­ing dis­eases, and were re­spon­si­ble for the can­di­date-gene de­ba­cle where al­most all can­di­date-gene hits were shown by later GWASes to be false pos­i­tives. In­deed, so op­posed to the stan­dard be­hav­ioral ge­net­ics par­a­digm were many re­searchers & com­men­ta­tors that they used the ini­tial GWAS null find­ings, in­di­cat­ing that the “” was due to poly­genic­ity with many small effects and thus re­quir­ing sam­ple sizes close to n > 100,000, as re­duc­tio ad ab­sur­dum which dis­proved the en­tire en­ter­prise; , of course, those sam­ple sizes were reached and the hits have kept com­ing ever since.

Why is this the case? Per­haps be­cause it suffers the dual prob­lem of be­ing offen­sively the­o­ret­i­cally sim­ple yet prac­ti­cally diffi­cult to deal with; early Mendelians (eg ) com­plained of the diffi­cul­ties of un­der­stand­ing Gal­ton, , or Fish­er’s math­e­mat­ics, while ap­ply­ing the sta­tis­tics at all must have been enor­mously painful in an era where even me­chan­i­cal cal­cu­la­tors were not al­ways avail­able, and the im­pli­ca­tions are that for some things like GWASes hun­dreds of thou­sands or mil­lions of sam­ples were re­quired, all in the ser­vice of a the­ory whose in­tel­lec­tual charm & sub­tlety are diffi­cult to ap­pre­ci­ate, and which seems prima fa­cie false to any­one fa­mil­iar with the in­tri­cate end­lessly com­plex path­ways and feed­back loops of real bi­o­log­i­cal sys­tems. And yet, ‘it moves’, for all the so­phis­ti­ca­tion and of Mendelian the­o­ries rev­el­ing in epis­ta­sis and dom­i­nance. It can be easy to read small n data in Mendelian ways, as­sum­ing away anom­alies as mea­sure­ment er­ror and the usual ‘crud fac­tor’ of sci­en­tific re­search—a strik­ing re­cent ex­am­ple is the 60-year-long mis­taken be­lief that re­sponse is a sin­gle Mendelian au­to­so­mal dom­i­nant trait based on ’s 34 cats which turns out to be when stud­ied more rig­or­ously with n~210. In ad­di­tion, the mono­genic ap­proach is in­dis­putably suc­cess­ful in de­scrib­ing many dra­matic ge­netic dis­eases. And, of course, the eu­gen­ics im­pli­ca­tions for hu­mans of Mendelian-style ge­net­ics are much less, in ex­actly the ways Her­bert in­ad­ver­tently il­lus­trates. So per­haps we should not be too hard on re­searchers who naively ex­pected to find a few dozen ge­netic vari­ants which could ac­count for most differ­ences in in­tel­li­gence or health, and which could be found look­ing un­der the lamp post us­ing easy sam­ples like n = 100.)

In par­tic­u­lar, as ex­tended by , it is heav­ily used in an­i­mal and plant breed­ing in cre­at­ing new strains of plants with a spe­cific de­sired trait, often crossed in from an­other va­ri­etal or even species. In those sce­nar­ios, where one is try­ing not to ex­ag­ger­ate ex­ist­ing traits but to copy an en­tire novel trait—re­sis­tance to a par­tic­u­lar pes­ti­cide or in­sect, per­haps, or salt re­sis­tance, or a coat col­or—there may be more than one ge­netic vari­ant at work, you may need a whole gene copied over from the other or­gan­ism, per­haps sev­eral of them work­ing in con­cert, act­ing epista­t­i­cal­ly, a “gene com­plex” as Wright dubbed them. Epis­ta­sis makes breed­ing diffi­cult be­cause the new set of genes might be bro­ken up im­me­di­ately by the re­com­bi­na­tion. If there are, say, 3 new genes brought over into an or­gan­ism and it has some off­spring with an un­mod­i­fied or­gan­ism, each off­spring will have, say, 1⁄23 = 1⁄8 odds of in­her­it­ing the full set of 3; so of 8 off­spring, per­haps 7 will not have the de­sired trait be­cause only the 8th man­aged to get all 3 si­mul­ta­ne­ous­ly. Only 1 or 2 is no good. These are not good odds and com­pli­cate things (if you can only see the re­sult when all 3 genes are in­herit­ed, how do you know whether there were 0, 1, or 2 in the ones with­out the trait?). As Lush puts it in his 1943 text­book:

Se­lec­tion for epista­tic effects is some­what like build­ing a sand pile on the seashore ex­posed to each in­com­ing wave. It is easy to build a lit­tle pile be­tween waves, but each wave which rolls over it tends to flat­ten out the pile. When build­ing is stopped, some traces re­main after the first wave and per­haps even a few after the sec­ond and third, but soon prac­ti­cally all traces of the pile are lev­eled away. If build­ing con­tin­ues be­tween waves, the pile can be built a lit­tle higher be­fore the sec­ond and third waves than it was built be­fore the first wave but soon a size is ap­proached which can just be main­tained, the build­ing be­tween waves be­ing just enough to re­pair the lev­el­ing ac­tion of the pre­ced­ing wave.

Or as would put it, di­rectly con­sid­er­ing hu­man ge­niuses (, 1978):

Truly ex­cep­tional in­di­vid­u­als, weak or strong, are, by de­fi­n­i­tion, to be found at the ex­tremes of sta­tis­ti­cal curves…S­ince each in­di­vid­ual pro­duced by the sex­ual process con­tains a unique set of genes, very ex­cep­tional com­bi­na­tions of genes are un­likely to ap­pear twice even within the same fam­i­ly. So if ge­nius is to any ex­tent hered­i­tary, it winks on and off through the gene pool in a way that would be diffi­cult to mea­sure or pre­dict. Like Sisy­phus rolling his boul­der up to the top of the hill only to have it tum­ble down again, the hu­man gene pool cre­ates hered­i­tary ge­nius in many ways in many places only to have it come apart in the next gen­er­a­tion.11

To in­ves­ti­gate or se­lect, one must carry out time-con­sum­ing and diffi­cult breed­ing of mul­ti­ple gen­er­a­tions, var­i­ous of re­lated or­gan­isms, and so on, and one can even­tu­ally de­duce all of the rel­e­vant pa­ra­me­ters and in­tro­duce every­thing enough times.

But… what you can do is, once you have man­aged the cross, cre­ate a line of or­gan­isms which breeds true for the trait by ex­ten­sive in­breed­ing or cloning, “line-breed­ing”. (The use of in­breed­ing for de­vel­op­ing new lines is gen­er­ally at­trib­uted to early Eng­lish breeder 12; breed­ers then avoided in­breed­ing as ‘in­cest’ and wor­ried about in­breed­ing de­pres­sion, en­gag­ing in ex­ten­sive cross-breed­ing of va­ri­eties, which while avoid­ing both of those prob­lems, dras­ti­cally slows down progress and ob­scures her­i­tabil­ity and in­evitably mud­dles any sharp dis­tinc­tion­s.) If you get say 16 off­spring from that or­gan­ism, and take the two sib­ling or­gan­isms with the trait, both of which you know have the full gene com­plex of 3 vari­ants, and you mate them, then all of their off­spring will ex­press the trait be­cause the 3 vari­ants have been fix­ated within that line. (This sort of in­ces­tu­ous in­breed­ing ap­proach would also help with purg­ing harm­ful re­ces­sives: be­cause they are so re­lat­ed, off­spring will often have two copies of a harm­ful re­ces­sive and it will im­me­di­ately cause ill health or death, rather than con­tinue float­ing around the gen­eral pop­u­la­tion.) Or you could clone them and en­sure the genes (and thus trait) is pre­served that way—­cloning is es­pe­cially com­mon in plants, and many fa­mous plant va­ri­eties are prop­a­gated clon­ally be­cause their char­ac­ter­is­tics would be lost if they were prop­a­gated sex­u­al­ly. ( are a fa­mous ex­am­ple: wild ap­ples ex­hibit tremen­dous va­ri­ety but typ­i­cally all taste bad and are use­ful mostly for mak­ing ; the su­per­mar­ket ap­ple va­ri­eties all stem from sin­gle “chance seedling” ap­ple trees dis­cov­ered on farms to be un­usu­ally tasty, and then are prop­a­gated clon­ally for com­mer­cial sale. The com­mem­o­rates the leg­endary dis­cov­ery of the pop­u­lar green ap­ple un­der­neath Maria Ann Smith’s kitchen win­dow, al­though it may also have been found grow­ing in a pile of dis­carded French crab-ap­ples, while was ac­ci­den­tally dis­cov­ered after a hur­ri­cane knocked down its sur­round­ing nor­mal ap­ple trees; ap­ple va­ri­eties can be dis­cov­ered when in­di­vid­ual limbs of trees mu­tate, cre­at­ing , see ///. Ba­si­cal­ly, ap­ples work in real life the way the X-Men work in fic­tion.) Then you can use that strain di­rect­ly, or em­ploy it in var­i­ous other breed­ing pro­grams while per­pet­u­at­ing the line in­defi­nite­ly. All of this is com­mon in, for ex­am­ple, plant cul­ti­vars or in the spe­cial mice & rat breeds (Green 1966) used in lab work. Or if a de­sired mu­ta­tion sud­denly pops up in an in­di­vid­u­al, per­haps en­cour­aged by the use of mu­ta­ge­n­e­sis like , the mu­ta­tion will be lost if it is not bred heav­i­ly, pos­si­bly with rel­a­tives. There can be ad­di­tional ad­van­tages to in­breed­ing se­lec­tion (see chap­ter 23/30 of the draft Walsh & Lynch text­book on se­lec­tion), es­pe­cially in sit­u­a­tions in which past gen­er­a­tions can be re-bred, such as with saved seeds or in the case of Dune, gho­las re­peat­edly cloned from old cells.

Bene Gesserit as Farmers

So—this al­ter­nate par­a­digm can neatly ex­plain all of the odd­i­ties of the Dune breed­ing pro­gram! The rea­son it is so odd is be­cause Her­bert was draw­ing on the ob­so­lete Mendelian in­ter­pre­ta­tions which were heavy on epis­ta­sis and de novo mu­ta­tions, as op­posed to the more plau­si­bly rel­e­vant bio­met­ric Fish­er­ian par­a­digm of highly poly­genic ad­di­tive traits with se­lec­tion on stand­ing vari­a­tion. Her­bert was through­out his life in­ter­ested in agri­cul­ture & ge­net­ics, as demon­strated by his demon­stra­tion home farm project and the re­peated use of agri­cul­tural themes in his works (eg Hell­strom’s Hive, where a group of hu­mans de­vel­ops into eu­so­cial in­sects, or The Green Brain, where hu­man ex­ter­mi­na­tion of in­sects has cat­a­stroph­i­cally desta­bi­lized global agri­cul­ture & pro­voked evo­lu­tion of in­tel­li­gent in­sect­s).

It ap­pears non­sen­si­cal if you aren’t fa­mil­iar with an­i­mal/­plant breed­ing, and stuff like broth­er-sis­ter mat­ing looks ar­bi­trary or a weird sex­ual fetish, but such sib­ling mat­ing is an es­tab­lished tac­tic for fix­at­ing a spe­cific set of mul­ti­ple genes which all de­pend on each other to work at all (epis­ta­sis) and com­mon in breed­ing. Hence, the rea­son the pro­gram took so many thou­sands of years is that they were wait­ing for de novos to pop up and were frag­ilely as­sem­bling mul­ti­ple gene com­plexes of epista­tic vari­ants. The BG had to main­tain an elab­o­rate pro­gram to hunt the hints of var­i­ous re­ces­sive/epista­tic pat­terns in their pedi­grees (“We Bene Gesserit sift peo­ple to find the hu­mans”), grad­u­ally con­cen­trat­ing sets of use­ful genes in prized aris­to­cratic lin­eages, and oc­ca­sional pre­ma­ture deaths or po­lit­i­cal er­rors could let slip a ball of yarn they had spent gen­er­a­tions grad­u­ally wind­ing. And there were no Siona no-genes float­ing around the gene pool for Leto II to se­lect on, he had to wait pa­tiently for it to pop up nat­u­rally in Siona. This is also why the Bene Tleilax could ob­serve “essences” in the wild13 or offhand­edly cre­ate their own Kwisatz Hader­ach: the BG & Leto II refuse to use any­thing but nat­ural pro­cre­ation, but the BT can edit and clone freely, which mas­sively speeds things up. Fi­nal­ly, this is why un­usual ge­net­ics jar­gon from the Mendelian tra­di­tion (like Leto II de­scrib­ing Dun­can Idaho as “a first-gen­er­a­tion cross”) pops up oc­ca­sion­ally in the nov­els.

This is not to say that this is a cor­rect view of hu­man ge­net­ics, or that Frank Her­bert nec­es­sar­ily had an ex­plicit idea of epis­ta­sis and de novo mu­ta­tions in mind while plot­ting out Dune, but it shows that in his wide read­ing (e­spe­cially re­lated to his hobby of farm­ing), he could eas­ily have picked up on ex­ist­ing re­search and meth­ods, and these in­flu­ences were wo­ven into his nov­els.

See Also

Appendix

Race in My Little Pony

(For back­ground on , .)

An­other fic­tional uni­verse with ge­netic mech­a­nisms is My Lit­tle Pony: Friend­ship Is Magic, where there are 3 pony races which are her­i­ta­ble. One out­lier fam­ily which has all 3 races rep­re­sented chal­lenges sim­ple Mendelian in­ter­pre­ta­tions of MLP races. I re­view 4 at­tempts to rec­on­cile the out­lier with Mendelian mech­a­nisms, and pro­pose an­other in­ter­pre­ta­tion, draw­ing on poly­genic mech­a­nisms, treat­ing race as a poly­to­mous li­a­bil­ity thresh­old trait, which is flex­i­ble enough to ex­plain all ob­ser­va­tions in­-u­ni­verse (at least for the first few sea­sons of MLP).

In My Lit­tle Pony: Friend­ship Is Magic, there are 3 ap­par­ently sep­a­rate & spe­cial­ized pony races: “Earth ponies” (phys­i­cally strong & nat­u­rally gifted at agri­cul­ture), the Pe­gasi (fliers who mag­i­cally ma­nip­u­late the weath­er), and Uni­corns (magic spe­cial­ist­s—the fourth type of pony, the al­l-fe­male “Al­icorns”, are ex­tremely rare and are usu­ally ex­plained as be­ing mag­i­cal); they are not sep­a­rate species and can in­ter­breed, but can be con­sid­ered breed­s/races: al­most all de­picted fam­i­lies are ho­moge­nous & have off­spring of the same race, they are clearly dis­tinct, dis­tantly re­lated (eg Pinkie Pie & the Ap­ples/­Pears), typ­i­cally re­pro­duce within their own race, and tend to clus­ter ge­o­graph­i­cally (with the noted ex­cep­tion of Ponyville).

All main char­ac­ters’ fam­i­lies are, as far as shown, the same race as their daugh­ter. The one ex­cep­tion is the Cake Fam­ily of bak­ers, where the two Earth ponies Mr. and Mrs. Cake have two chil­dren in sea­son 2 episode 13 (“Baby Cakes”), a pair of fra­ter­nal twins, who are dis­cor­dan­t—Pe­gasi and Uni­corn. When queried by the con­fused main char­ac­ters, Mr Cake ap­peals to a vague ge­netic ex­pla­na­tion, claim­ing “My great-great-great-great grand­fa­ther was a uni­corn, and Cup Cake’s great aun­t’s sec­ond cousin twice re­moved was a Pe­ga­sus. That makes sense, right?”

The puz­zle here is how can we ex­plain that al­most all fam­i­lies ex­cept the Cakes are ho­moge­nous in pony race, but it is still pos­si­ble for one (or two) oc­ca­sional dis­cor­dant off­spring?

A poly­to­mous is suffi­ciently flex­i­ble as to ex­plain all of these pat­terns by sim­ply set­ting thresh­olds ap­pro­pri­ately and ex­pect­ing as­sor­ta­tive mat­ing. For ex­am­ple, there could be a sin­gle race trait which is poly­to­mous with 2 in­de­pen­dent thresh­olds, Pe­gasi | Earth | Uni­corn, and the thresh­olds are set suffi­ciently ex­treme as to en­sure most fam­i­lies of 2–3 chil­dren (MLP fam­i­lies tend­ing to the very small) are ho­moge­nous, such as at −2SD and +2SD. Then en­sures that most Pe­gasi fam­i­lies have a ‘race trait’ mean some­where well be­low −2SD, Earth fam­i­lies have a mean ~0, Uni­corn fam­i­lies have a mean trait >2, etc. Then, if Mr Cake is un­usu­ally close the 2SD thresh­old and Mrs Cake is un­usu­ally close to the Pe­ga­sus thresh­old, the two fra­ter­nal twins could in­herit differ­en­tially from their par­ents and wind up be­ing pushed across differ­ent thresh­olds. (Si­b­lings/fra­ter­nal twins may both in­herit 50% from each par­ent, but they will in­herit differ­ent 50%s at ran­dom due to the ran­dom­iza­tion of , and their re­lat­ed­ness to each other can eas­ily be ±5%, so in a par­tic­u­larly ex­treme case per­haps that would be enough.) Al­ter­nate­ly, it could be de­ter­mined by mul­ti­ple bi­nary li­a­bil­ity thresh­old traits, one for each race, and the ex­pressed race is sim­ply the max­i­mum of the 3 trait val­ues; in which case sim­i­lar logic holds for the two twins. The mane prob­lem, you might say, with the li­a­bil­ity thresh­old model is that it is, if any­thing, too flex­i­ble and so it’s hard to pro­vide good ev­i­dence pick­ing it out with just the MLP ev­i­dence. (In real world ge­net­ics, one could ac­cu­mu­late ev­i­dence for a li­a­bil­ity thresh­old model by ex­am­in­ing ‘risk’ in in­creas­ingly dis­tant rel­a­tives and whether it drops off with ge­netic dis­tance as it should, look­ing for con­tin­u­ous mea­sure­ments re­flect­ing an in­creased ge­netic trait value like de­pressed IQ or schiz­o­phre­nia symp­toms in rel­a­tives of schiz­o­phren­ics, or us­ing mol­e­c­u­lar ge­netic meth­ods like or to see if a bi­nary trait is highly poly­genic, etc, but none of that is pos­si­ble here.)

A Mendelian model is a lit­tle harder to come up with but there are at least 4 at­tempts. Hel­loNurse sug­gests a mono­genic model with 3 al­le­les each caus­ing a differ­ent race, Earth pony dom­i­nance, and epis­ta­sis or en­vi­ron­men­tal ran­dom­iza­tion (ie low pen­e­trance):

Mendelian ponies could have a sin­gle gene with 3 al­le­les, E/U/P, with EE, EU and EP earth, UU and PP re­spec­tively uni­corn and pe­ga­sus and UP ei­ther uni­corn or pe­ga­sus at ran­dom (i.e. de­pend­ing on other genes). If the two par­ents are EU and EP they are earth but off­spring of all three types is pos­si­ble. An even sim­pler mod­el: one gene with two al­le­les, earth and fan­cy, earth dom­i­nant, fancy ponies be­come uni­corns or pe­gasi de­pend­ing on rain­bow in­ten­sity or other non-ge­netic fac­tors.

Grim-S-Mor­ri­son gives a 2 gene mod­el, with a dom­i­nan­t/re­ces­sive Earth­/U­ni­corn effect and a dom­i­nan­t/re­ces­sive Pe­ga­sus/U­ni­corn, giv­ing a Pun­net ta­ble (re­pro­duc­ing in Mark­down):

Grim S Mor­rison’s 2-gene model us­ing Earth pony dom­i­nance; hy­po­thet­i­cal for Mr & Mrs. Cake
EuPu (Earth par­ent)
EuPu (Earth par­ent) EP Eu uP UU
EP (Earth) EEPP (Earth) EEPu (Earth) EuPP (Earth) EuPu (Earth)
Eu (Earth) EEPu (Earth) EEuu (Earth) EuPu (Earth) Euuu (Earth)
uP (Earth) EuPP (Earth) EuPu (Earth) uuPP (Pe­ga­sus) uuPu (Pe­ga­sus)
uu (Earth) EuPu (Earth) Euuu (Earth) uuPu (Pe­ga­sus) uuuu (U­ni­corn)

This ad­mit­tedly has some prob­lems ex­plain­ing why Pe­gasi and Uni­corns ap­pear to be quite com­mon in Eques­tria; it would re­quire an ex­treme caste sys­tem to keep Pe­gasi & Uni­corn fam­i­lies highly ho­moge­nous & a large frac­tion of the pop­u­la­tion, rather than be­ing sub­merged in Earth ponies and mostly pop­ping up in Earth pony fam­i­lies, which is so rare that mul­ti­ple adult ponies could be quite sur­prised at any dis­cor­dance. And of course, if two Pe­gasi ever have Earth pony off­spring (rather than Pe­gasi or Uni­corn) or two Uni­corns are ever shown as hav­ing non-U­ni­corn off­spring, the model would be im­me­di­ately fal­si­fied.

Fi­nal­ly, Tad Stone & So­ryu Aleksi take as a start­ing point that Earth ponies are much more com­mon, and Uni­corns rare; they don’t try to ex­plain to ex­plain Al­icorns. They also go with a block­ing method:

Go­ing from here, the ponies would have two genes, a Uni­corn and a Pe­ga­sus gene. Both genes have a dom­i­nant al­lele that blocks the de­vel­op­ment of wings or horns re­spec­tive­ly, and a re­ces­sive one to de­velop the fea­tures:

  • P: Pe­ga­sus blocker
  • p: Pe­ga­sus
  • U: Uni­corn blocker
  • u: Uni­corn

An Earth pony is a pony where both genes con­tain at least one block­ing al­lele…The pos­si­bil­i­ties then are as fol­lows:

Tad Stone & So­ryu Aleksi 2-gene mod­el, racial types
Race Pos­si­ble al­lele com­bi­na­tions
Earth pony PPUU, PpUU, PPUu, PpUu
Pe­ga­sus ppUU, ppUu, ppuu
Uni­corn PPuu, Ppuu

This would make Mr and Mrs Cake’s chil­dren pos­si­ble if both par­ents are PpUu:

Tad Stone & So­ryu Aleksi 2-gene mod­el, Pun­nett square
PU Pu pU pu
PU PPUU (Earth) PPUu (Earth) PpUU (Earth) PpUu (Earth)
Pu PPUu (Earth) PPuu (U­ni­corn) PpUu (Earth) Ppuu (U­ni­corn)
pU PpUU (Earth) PpUu (Earth) ppUU (Pe­ga­sus) ppUu (Pe­ga­sus)
pu PpUu (Earth) Ppuu (U­ni­corn) ppUu (Pe­ga­sus) ppuu (Pe­ga­sus)

Of course this would mean that Mr and Mrs Cake each have a (pos­si­bly very dis­tant) Pe­ga­sus and a Uni­corn an­ces­tor. How­ev­er, in the se­ries only a Pe­ga­sus cousin for Mrs Cake and a Uni­corn for Mr Cake are named. With only these two as non-Earth pony an­ces­tors it would not be pos­si­ble fol­low­ing my own the­o­ry, but in all like­li­hood they don’t know all their an­ces­tors. Also a pretty com­pli­cated com­bi­na­tion of genes would be needed in that case and we can’t de­scribe such a thing with­out know­ing much, much more.

This ex­pla­na­tion works nicely and vi­o­lates the min­i­mum of el­e­ments.

There are some fur­ther the­o­ries which I think are in­con­sis­tent with the ev­i­dence:

  • Co­coaNut­Cak­ery sug­gests a more com­pli­cated epis­ta­sis, ex­plain­ing the non-ob­served com­bi­na­tions as be­ing fa­tal/pro­duc­ing non­vi­able em­bryos, and ex­plain­ing the Earth pony-like magic of Flut­ter­shy (a Pe­ga­sus) as be­ing due to ad­di­tional magic re­sis­tance & ex­plain­ing Al­icorns sim­i­lar­ly; this has the se­ri­ous de­fect of re­quir­ing Uni­corn & Pe­gasi fam­i­lies to have much lower fer­til­ity or se­vere in­fant mor­tal­ity rates (which are not sup­ported in canon and are rather against the spirit of the show).
  • theace­of­s­padez’s “The Ge­net­ics of the Pony: The Nel­son The­ory for Pony In­her­i­tance” founders on at­tempt­ing to ex­plain too much and mak­ing Al­icorns far too fre­quent, and also pos­tu­lat­ing “Al­icorn Earth­/Pe­ga­sus/U­ni­corn” vari­ants too.
  • Tac­ti­cal­rain­boom’s en­vi­ron­men­tal de­ter­mi­na­tion the­ory ar­gues that it’s not ge­netic at all but en­vi­ron­men­tal (eg Pe­gasi are caused by ex­po­sure to high al­ti­tude & weather mag­ic), but this is quite a stretch as it can’t ex­plain why Earth ponies col­o­niz­ing new places have Earth pony off­spring (eg. the en­tire Ap­ple clan from many differ­ent lo­ca­tions through­out Eques­tria are all Earth ponies), what en­vi­ron­ment Mane­hat­tan & Ponyville have in com­mon caus­ing Earth ponies but which the cap­i­tal city of Can­ter­lot does not to cause mostly Uni­corns, or why, if de­vi­a­tions from the lo­cal norm are due to ran­dom en­vi­ron­men­tal fluc­tu­a­tions, both Cake twins would be dis­cor­dant in­stead of be­ing the same type (pre­sum­ably any ran­dom en­vi­ron­men­tal fluc­tu­a­tion affect­ing Mrs. Cake ought to affect the fra­ter­nal twin fe­tuses si­mul­ta­ne­ously & equally).

But wait­—there are more pos­si­ble ex­pla­na­tions! Could Mrs. Cake have been cheat­ing on Mr. Cake or they did a three­some, since fra­ter­nal twins don’t have to be fer­til­ized by sperm from the same fa­ther, and this is why he had shifty eye­s/was vague? Were sur­ro­ga­cies and/or egg/sperm donors in­volved, be­cause one or both of the Cakes are in­fer­tile? Or could the twins have been affected pre­na­tally by Dis­cord at the be­gin­ning of sea­son 2? Or per­haps ponies are not even diploid (so all the Mendelian ex­pla­na­tions are fun­da­men­tally wrong), but , in which case just about any kind of in­her­i­tance is pos­si­ble?

That said, re­view­ing the the­o­ries, I think my poly­genic thresh­old mod­els or Tad Stone’s two-gene model fit the best over­all.


  1. Frank Her­bert, “Lis­ten­ing to the Left Hand”, Harper’s (De­cem­ber 1973):

    …We tend to re­act to­gether with a re­mark­able de­gree of sim­i­lar­ity across bound­aries that are real only to in­di­vid­ual cells, but re­main trans­par­ent to the species. We tend to go psy­chotic to­geth­er.

    Touch one part and all re­spond.

    The to­tal­ity can learn.

    This im­plies a non­ver­bal chem­istry of species-wide com­mu­ni­ca­tion whose work­ings re­main largely un­known. It im­plies that much of our col­lec­tive be­hav­ior may be pre­planned for us in the form of mech­a­nisms that over­ride con­scious­ness. Re­mem­ber that we’re look­ing for pat­terns. The wild sex­u­al­ity of com­bat troops has been re­marked by ob­servers through­out recorded his­tory and has usu­ally been passed off as a kind of boys-will-be-boys vari­a­tion on the male mys­tique. Not un­til this cen­tury have we be­gun to ques­tion that item of con­sen­sus re­al­ity (read The Sex­ual Cy­cle of Hu­man War­fare by N.I.M. Wal­ter). One of the themes of my own sci­ence fic­tion nov­el, Dune, is war as a col­lec­tive or­gasm. The idea is com­ing un­der dis­cus­sion in eru­dite jour­nals such as the Gen­eral Sys­tems Year­book. …

    • Some­thing like pheromones (ex­ter­nal hor­mones) in­ter­act­ing be­tween mem­bers of the hu­man species to weld groups into col­lec­tive-ac­tion or­gans. (How does a mob unite and hold it­self to­geth­er?)
    • Iso­la­tion cues that sep­a­rate groups into iden­ti­fi­able sub­struc­tures, a sys­tem pos­si­bly in­flu­enced by di­et. (A­side from ac­cent and man­ner­ism, how do mem­bers of the British up­per class rec­og­nize each oth­er?)

    Wal­ter’s book, as hard to get as it is (it has never been reprint­ed), oc­ca­sion­ally sur­faces in odd places. For ex­am­ple, was im­pressed enough to spend sev­eral pages de­scrib­ing it in his 2006 au­to­bi­og­ra­phy Con­fes­sions Of The Fa­ther Of The Neu­tron Bomb. Co­hen, in­ci­den­tal­ly, gives some of the few bi­o­graph­i­cal de­tails about Wal­ter I’ve seen:

    When I had fin­ished Wal­ter’s book, through the pub­lisher I wrote a long let­ter to him, telling him how im­pressed I was and ask­ing about his back­ground—cer­tain it was aca­d­e­mic, that he was a pro­fes­sor of in­ter­na­tional re­la­tions, or phi­los­o­phy, or an­thro­pol­ogy at some pres­ti­gious British uni­ver­si­ty. Some weeks lat­er, I re­ceived a re­ply thank­ing me for my kind words and telling me I was lit­er­ally the only one to write to him about his book. As for his back­ground, no he was­n’t a pro­fes­sor. He had grad­u­ated from Sand­hurst (the British West Point) and after a very long ca­reer re­tired as a colonel. He had been a com­bat in­fantry offi­cer, fight­ing mainly to pro­tect the Em­pire—in Africa, the Mid­dle East, Asia, wherever; and fi­nally in World War I and II. Over all these years of fight­ing and see­ing war in the raw and coun­tries gripped in the throes of war, this sex­ual theme grad­u­ally dawned upon him. He vowed that when his ca­reer ended he would write a book about it. Which he did, but was un­able to get a pub­lish­er, so he dipped into his mea­ger pen­sion and had 500 copies printed at his own ex­pense, most of which never sold.

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  2. “Frank Her­bert LP: the Ban­quet Scene”:

    Dune, of course, takes you through the cre­ation of the su­per­hero, Paul Atrei­des, who be­comes the Mahdi of the Fre­men. Please fo­cus on that word cre­ation be­cause many of the el­e­ments which go into the mak­ing of the su­per­hero are laid out for you in this work. You have here a kind of dis­til­la­tion of an aris­to­cratic bu­reau­cra­cy, one of whose un­men­tioned an­ces­tors is the So­viet ex­per­i­ment. You are taken through a his­tory of many power in­stru­ments which have been tried and dis­carded (or adapted to new form­s).

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  3. It’s worth not­ing that the an­ces­tral mem­o­ries are prob­a­bly part of the KH pack­age and rely on pre­science. The usual in­ter­pre­ta­tion by read­ers that an­ces­tral mem­o­ries are en­coded into DNA and passed on that way may be an over-read­ing of the men­tions of DNA: en­cod­ing into DNA does­n’t make any sense be­cause it would im­ply, among other things, that an­ces­tral mem­o­ries work only for di­rect an­ces­tors, can­not re­call any­one whose lin­eage went ex­tinct, can­not re­call any­thing in an an­ces­tor’s life after fer­til­iza­tion of their chil­dren, can­not re­call dy­ing (ex­cept for gho­las), ought to de­cay or mu­tate over many mil­len­nia, have lim­ited ca­pac­i­ty, etc, and can­not ex­plain how the Dun­can Idaho ghola even­tu­ally re­calls mem­o­ries from all his gho­las, even ones whose cells were never used in the fi­nal gho­la! So the con­nec­tion of DNA to an­ces­tral mem­o­ries is prob­a­bly more in the role of a ‘key’ or ‘in­dex’ where re­lat­ed­ness opens up ac­cess across time.↩︎

  4. The gen­eral theme through­out the Dune se­ries of hu­mans be­com­ing ever more ca­pa­ble and flex­i­ble gen­er­al­ists is un­de­ni­able, but the ul­ti­mate cul­mi­na­tion in democ­racy is a lit­tle doubt­ful; Her­bert was not a fan of dic­ta­tor­ship or monar­chies, de­spite those be­ing about the only forms of gov­ern­ment de­pict­ed, and it seems to be con­sis­tent with a few pas­sages like the dis­cus­sions of the Hon­ored Ma­tres, but the only source for democ­racy as the end-game is a late rec­ol­lec­tion in Jan­u­ary 2009 by :

    SR: Do you be­lieve Frank had in­ten­tions of a “Dune 7”? Along the same lines, what do think of the claim of Brian Her­bert to have found floppy disks con­tain­ing the “com­plete” Dune 7 out­line in a safety de­posit box years after Frank’s death? If there were notes, do you be­lieve Brian and Kevin J. An­der­son used them faith­fully in their new “Dune” books?

    NS: Maybe. Frank kept go­ing as long as the big money kept rolling in. Know­ing Frank’s po­lit­i­cal phi­los­o­phy, I once asked him how he could keep writ­ing this roy­al­ist stuff. He told me he planned to end the se­ries with a novel that would tran­si­tion to a fic­tional uni­verse of de­mo­c­ra­tic rule. Never wrote it, of course. And Brian and Kevin cer­tainly did­n’t from any 7 notes.

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  5. From Chil­dren of Dune:

    “If … if Jes­sica has gone back to the Sis­ter­hood com­pletely …”

    “That’d be very dan­ger­ous to us,” he said, com­plet­ing the thought. “We carry the blood of their Kwisatz Hader­ach—their male Bene Gesser­it.”

    “They won’t aban­don that search,” she said, “but they may aban­don us. Our grand­mother could be the in­stru­ment.”

    “There’s an­other way,” he said.

    “Yes—the two of us . . . mat­ed. But they know what re­ces­sives might com­pli­cate that pair­ing.”

    “It’s a gam­ble they must’ve dis­cussed.”

    “And with our grand­moth­er, at that. I don’t like that way.” “Nor I.”

    “Still, it’s not the first time a royal line has tried to . . .”

    “It re­pels me,” he said, shud­der­ing. She felt the move­ment, fell silent. “Power”, he said.

    And in that strange alchemy of their sim­i­lar­i­ties she knew where his thoughts had been. “The power of the Kwisatz Hader­ach must fail,” she agreed. “Used in their way,” he said…“You are not Osiris.” Ghan­ima re­minded him. “Nor will I try to be.”

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  6. GEoD: Leto II says “The Sis­ter­hood has never for­given me for tak­ing their breed­ing pro­gram away from them” in dis­cussing mo­tives the BG would have for act­ing against him.↩︎

  7. In God Em­peror of Dune, Leto II’s 118 year old ma­jor­do­mo, Mo­n­eo, ini­tially dis­ap­proves of the use of orig­i­nal Dun­can Idaho gho­las, not­ing that “The Dun­cans are slower and less alert than any­one in your Guard.” Leto II points out that us­ing Idaho “gives me ac­cess to a first-gen­er­a­tion cross be­tween an older hu­man form and the cur­rent prod­ucts of my breed­ing pro­gram. Siona is 21 gen­er­a­tions from such a cross.” Dun­can later at­tacks Mo­neo and is eas­ily de­feat­ed:

    “You just haven’t the guts to pay the price he’s ask­ing”, Mo­neo said.

    In one blurred mo­tion, Idaho whipped his knife from its sheath and lunged at Mo­n­eo. As fast as he moved, Mo­neo moved faster—­side­step­ping, trip­ping Idaho and pro­pelling him face-down onto the floor. Idaho scram­bled for­ward, rolled and started to leap to his feet, then hes­i­tat­ed, re­al­iz­ing that he had ac­tu­ally tried to at­tack an Atrei­des. Mo­neo was Atrei­des. Shock held Idaho im­mo­bile. Mo­neo stood un­mov­ing, look­ing down at him. There was an odd look of sad­ness on the ma­jor­do­mo’s face.

    “If you’re go­ing to kill me, Dun­can, you’d best do it in the back by stealth”, Mo­neo said. “You might suc­ceed that way.”

    Idaho lev­ered him­self to one knee, put a foot flat on the floor, but re­mained there still clutch­ing his knife. Mo­neo had moved so quickly and with such grace, so . . . so ca­su­al­ly! Idaho cleared his throat. “How did you. . .”

    “He has been breed­ing us for a long time, Dun­can, strength­en­ing many things in us. He has bred us for speed, for in­tel­li­gence, for self­-re­straint, for sen­si­tiv­i­ty. You’re. . . you’re just an older mod­el.”

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  8. It’s worth not­ing that Frank Her­bert orig­i­nally worked as a jour­nal­ist and did not have a track record of de­vel­op­ing things for long pe­ri­ods or tak­ing ex­ten­sive notes, aside from the orig­i­nal Dune tril­o­gy, where he notes in an Omni es­say (“Dune Gen­e­sis”) that “I con­ceived of a long nov­el, the whole tril­ogy as one book about the mes­sianic con­vul­sions that pe­ri­od­i­cally over­take us.”, and in the pref­ace to Heretics of Dune that “Parts of Dune Mes­siah and Chil­dren of Dune were writ­ten be­fore Dune was com­plet­ed. They fleshed out more in the writ­ing, but the es­sen­tial story re­mained in­tact.”↩︎

  9. Note that Ra­m­agopalan et al 2007 sug­gest HP magic is a few-gene model dri­ven by dom­i­nance, which is an im­prove­ment over the sim­plis­tic (to the point of sim­ple-mind­ed­ness) re­ces­sive mono­genic magic model of , but—Kleno­tiz 2012’s ex­otic mono­genic dom­i­nant model in­vok­ing -like dy­nam­ics notwith­stand­ing—the ev­i­dence they give is equally or even more con­sis­tent with magic be­ing a con­tin­u­ous trait (with per­haps a thresh­old), dri­ven by poly­genic ad­di­tive vari­ants.↩︎

  10. The pony races are a lit­tle diffi­cult to ex­plain un­der a sim­ple Mendelian par­a­digm be­cause of an Earth pony cou­ple who have Pe­ga­sus and uni­corn chil­dren. For de­tails, see the ap­pen­dix.↩︎

  11. For some more on this idea of ge­nius, see John­son & Bouchard 2014, ; Si­mon­ton 1999, ; Lykken et al 1992, ; Lykken 2008, “The Ge­net­ics of Ge­nius”; Lykken 2006, ; Lykken 1982, ; Si­mon­ton 2005, .↩︎

  12. For more back­ground, see .↩︎

  13. If the ex­tremes of no­bil­ity or sadism or KH-ness the Bene Tleilax are in­ter­ested in are dri­ven by de novo mu­ta­tions or oc­ca­sional freak ag­gre­ga­tions of com­plex­es, this will hap­pen once in a while ob­serv­ing on a scale of cen­turies & in­ter­stel­lar-sized hu­man pop­u­la­tions, in the same way that al­binism and other bizarre traits can pop up at ran­dom, ei­ther by a chance mu­ta­tion or by a chance ag­gre­ga­tion of re­ces­sives etc. In­deed, it has been noted that the cur­rent hu­man pop­u­la­tion is large enough that any mu­ta­tion in the hu­man genome not quickly fa­tal can prob­a­bly be ob­served some­where in the cur­rent pop­u­la­tion, and the ab­sence of any car­rier of a par­tic­u­lar mu­ta­tion is a strong in­di­ca­tor that it would be a lethal mu­ta­tion (be­cause every­one with it died).

    In con­trast, if the ex­tremes in ques­tion were con­tin­u­ous poly­genic ad­di­tive traits where the ex­treme was some­thing like 10 or 20 stan­dard de­vi­a­tions from the norm, wait­ing for an ex­treme to ap­pear nat­u­rally would re­quire wait­ing the age of the uni­verse (ie nev­er); this is be­cause ran­dom fluc­tu­a­tions are van­ish­ingly un­likely to drive any in­di­vid­ual that far away from the mean. So, for ex­am­ple, it is quite com­mon to ob­serve dwarfism or gi­antism due to rare dis­eases or ge­netic dis­or­ders or mu­ta­tions of large effect, but one will never ob­serve a 3-me­ter-tall man caused by just com­mon ge­netic vari­ants at their cur­rent mean fre­quen­cies.↩︎