A phenotypic view of evolution Evolution in Structured Populations

Why reductionism DOES work: Individuals to genes

In the last couple of posts I have suggested that reductionism is for chumps. Two weeks ago I argued that gene interactions made average effects wonder around all over the place, and last week I argued that indirect genetic effects mucked up the works if there was population structure. This would seem to imply that …

Why reductionism doesn’t work, Part 2: Groups to individuals

Williams (1966) famously wrote “In explaining adaptation, one should assume the adequacy of the simplest form of natural selection, that of alternative alleles in Mendelian populations, unless the evidence clearly shows that this theory does not suffice.” This principle of parsimony makes two interesting points. The first phrase “In explaining adaptation” makes the point that …

Why reductionism doesn’t work; Part 1, Individuals to genes

One thing that often used to happen, perhaps not so much any more, is that people will say that we don’t need to worry about levels of selection because all selection can be reduced to selection acting directly on genes. George Williams perhaps put this view best, first with his principle of parsimony, which argues …

Epistasis in Monkey Flowers, and some general thoughts on epistasis

So, at least my twitterverse has been on fire suddenly with the appearance of a new article in PLoS by Patrick Monnahan and John Kelly “Epistasis Is a Major Determinant of the Additive Genetic Variance in Mimulus guttatus”  . It really is a nice study in which they identified 11 quantitative trait loci (QTL) in …

Matrix comparisons: Random skewers and selection skewers

A week late and a dollar short, but lets continue comparing matrices. Continuing on with my blatant endorsement of statistical methods attached to my name. . .  Last time I talked about the “Rank”/“Signed Bartlett”/”Modified Mantel” tests for comparing the dimension size and shape of a pair of matrices. This is only one of several …

What is “additive variance” in genetically uniform populations?

I recently got a comment from Michael Bentley at Oxford pointing out that he had a different interpretation of heritability among cells within higher organisms. His comment was: “Please could I just clarify something you say in this piece, as it relates to something I’m working on at the moment. You say: ‘From the perspective …

More on fitness assignments and individuality

In my last post I briefly mentioned that the level at which fitness is assigned is an interesting problem, but not a conundrum, or a serious conceptual issue. I think it would actually be quite useful to expand on this. The basic ideas came out of discussions I had 20 some odd years ago separately …

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