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All of EmilOWK's Comments + Replies

Heritability: Five Battles
EmilOWK50

Overall a sensible introduction. Turkheimer is very leftist by the field's standards, you may want to try out some others for opposite political slant or no slant. Not all authors color their work so heavily as he does.

You make a mistake in your terminology. Epistasis is not the same as nonlinearnity. Linearity stands in contrast to nonlinearity, which is called dominance. This is when a subject's phenotype does not change in a linear fashion from changing the alleles. So e.g., the change from TT to AT to AA does not have equal steps. This is common with s... (read more)

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4tailcalled
Dominance is (a certain kind of) nonlinearity on a single locus, epistasis is nonlinearity across different loci.
2Steven Byrnes
See §4.4.3 for my response. See the collapsible box labeled “Box: Twin-study evidence of epistasis in adult personality, mental health, and behavior” in §4.4.2 for many apparent examples of precisely this. Do you disagree with that? Is there more evidence I’m missing? Remember, I’m claiming that non-additive genetics are important in adult personality, mental health, and behavioral things like divorce, but that they’re NOT very important in height or blood pressure or (I think) IQ or EA. This is very possible!! It wouldn’t be the first time. I can still make changes. I found the use of terminology in the literature confusing … and I find your comment confusing too.  :( My background is physics not genetics, and thus I’m using the word “nonlinearity” in the linear algebra sense. I.e., if we take a SNP array that measures N SNPs, we can put the set of all possible genomes (as measured by this array) into an N-dimensional abstract vector space, I think. Then there’s a map from this N-dimensional space to, let’s say, extroversion. Both what you call dominance, and what you call epistasis, would make this map “nonlinear” (in the linear algebra sense). See what I mean? If it’s true that people in genetics use the term “nonlinearity” to refer specifically to nonlinearity-at-a-single-locus, then I would want to edit my post somehow! (Is it true? I don’t want to just take your word for it.) I don’t want people to be confused. However, nonlinearity-in-the-linear-algebra-sense is a very useful notion in this context. I will feel handicapped if I’m forbidden from referring to that concept. Maybe I’ll put in a footnote or something? Or switch from “nonlinearity” to “non-additivity”? (Does “non-additivity” subsume both dominance and epistasis?) Update: I replaced the word “epistasis” with “non-additive genetic effects” in a bunch of places throughout the post. Hopefully that makes things clearer??
What is Intelligence?
EmilOWK90

You do realize that there's >100 years of research on this topic about human cognitive abilities/intelligence? Reading this literature requires some understanding of statistics, but you would do well to read Stuart Ritchie's, Deary's or Haier's recent book length summaries of the area. Arthur Jensen's book is the best, but it's not an easy read.

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Stupidity as a mental illness
EmilOWK00

Multiple selection is discussed in the animal breeding literature. See e.g. this review.

Samorè, A. B., & Fontanesi, L. (2016). Genomic selection in pigs: state of the art and perspectives. Italian Journal of Animal Science, 15(2), 211–232. doi.org/10.1080/1828051X.2016.1172034

Sometimes the traits selected for are negatively genetically correlated. This slows down the process, but does not make it impossible unless the genetic correlation is -1.00. For humans, most of the traits we want seem to be positively related, with a few exceptions. Sometimes bi... (read more)

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