A phenotypic view of evolution Evolution in Structured Populations

Physiological and Statistical Epistasis

Last week I gave an informal seminar for our Friday lunch group, and realized that not everybody knows what I am talking about when I talk about epistasis.  I didn’t do a “what is epistasis” post originally because this was supposed to be a blog about the phenotype, and well, epistasis is genetics.  That said, …

Metapopulation Quantitative Genetics

Last week I talked about how Fisher’s original definition of additive genetic variance failed when average effects don’t equal average excesses. Basically this happens when ever there is some form of linkage disequilibrium. This gives us the easiest framework in which to think about this situation, that is in a “metapopulation”. A metapopulation is a …

Of Average Effects, Average Excesses and Additive Variance

Today’s post is a bit of a CYA (cover your a__) post.  I once got in a bit of a kerfuffle with Warren Ewens over my loose use of the concept of additive genetic variance.  It was a little like me bringing a knife to a gunfight.  I was hopelessly outclassed by his intellect, and …

Sewall Wright, Speciation and Migration

Many thanks to several members of the Zufall lab for bringing me up to date on mutation accumulation experiments .  Her lab is actively involved in MA experiments (http://www.genetics.org/content/early/2013/07/29/genetics.113.153536.abstract), and what was satisfying to me, quite interested in dissecting out dominance and epistatic effects of new mutants.  Hopefully we will get more data on this …

Mutation accumulation experiments

It is important to recognize that the need to move over to a phenotypic view of evolution is not just about incorporating continuous inheritance into the transition equation.  Even restricting ourselves to particulate inheritance and nuclear genetics the phenotypic approach gives insights that are simply missed using a genic approach.  In this post I talk …

A quick overview of genetic mutations

The third force of evolution is mutation.  There are a lot of platitudes and details about mutation that we just don’t need to care about.  One of my favorites is that (genetic) mutation is both the weakest and strongest evolutionary force.  Weakest because at least genetic mutations occur at a very low rate, and have …

Drift of continuous traits.

Wikipedia claims that there are no formal models of blending inheritance, although I would be inclined to disagree with this, as Fisher 1930 discusses blending inheritance in enough detail to call it a formal model.  Further, one older web site defines blending inheritance as “A discredited model of inheritance suggesting that the characteristics of an …

Drift and Epistasis: The odd effects of small population sizes

This week I want to return to specifically genetic drift (as opposed to drift in general).  First, a bit of history.  Back in 1984 there was a pair of competing articles on founder event speciation.  In that exchange Barton and Charlesworth (1984. Annual Review of Ecology and Systematics 15: 133-164) responding to Carson and Templeton …

How to include group selection without really trying: Adding contextual traits to a selection analysis

Last week I introduced the multivariate breeders equation.  Before moving on I want to talk a little about the types of traits that can be included in the selection vector.  Of course it is logical enough to include morphological traits such as body size or leaf area.  Only slightly more complicated are behavioral traits, and …

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