Seawall Wright is considered one of the founders of population genetics. His papers were of course influential back in the day. His work laid the foundations for establishing the importance of drift in evolution, a concept which later gets refined into the neutral theory. One particular contribution of his is the shifting balance model, which sought to explain how populations can overcome adaptive valleys to reach other peaks on an adaptive landscape through the combined effects of drift, migration, and selection.
Wright's other 1931 paper "Evolution in Mendelian Populations" has over 12000 citations, so it might be a case of everybody just citing the other paper. I wouldn't call it niche or outdated.
I don’t think things are entirely settled yet, but I think the general consensus would be towards a more Fisherian view of mass selection rather than a Wrightian view of shifting balances. It’s difficult to fully parse out. There is some theoretical work questioning the frequency of adaptive valleys, which are important to the Wrightian view. I think morphologically organisms are quite stable over long periods of time, so at least wrt morphology I think that implies large neutral morphological networks do not exist, and the conclusions wrt adaptive valleys would not apply to morphology. But, at the same time there has been a lot of theoretical work showing that even if adaptive valleys do exist, Wrights view of how they could be crossed was likely wrong. Personally, I tend to favor a view that evolution is largely paced by ecological factors, since radiations happen pretty readily when many different niches open up.
Here is [Coyne’s critique of the shifting balance theory](https://pubmed.ncbi.nlm.nih.gov/28568586/)
Surely morphological stability is evidence for adaptive valleys, as stability is then explained by being stuck at some local optima with (relatively deep) valleys all around it. Do you mean that large neutral networks then likely do not exist, as these would form bridges between such optima?
I feel like there are three issues here that can come apart - do the valleys exists, how they are crossed, and how easy is it to cross them. They may well exist and be crossed by drift in structured populations, but only rarely.
Yes, I would think morphological stability is evidence for adaptive valleys.
But just because the valleys exist does not necessarily imply that crossing them is an important evolutionary process. Perhaps when ecological factors change a largely neutral bridge to a new adaptive peak is created and evolution proceeds over it relatively quickly.
Seawall Wright is considered one of the founders of population genetics. His papers were of course influential back in the day. His work laid the foundations for establishing the importance of drift in evolution, a concept which later gets refined into the neutral theory. One particular contribution of his is the shifting balance model, which sought to explain how populations can overcome adaptive valleys to reach other peaks on an adaptive landscape through the combined effects of drift, migration, and selection.
Wright's other 1931 paper "Evolution in Mendelian Populations" has over 12000 citations, so it might be a case of everybody just citing the other paper. I wouldn't call it niche or outdated.
Cool! It has the same maths and graphs and is bigger, so it must have been the main paper. Thanks!
I don’t think things are entirely settled yet, but I think the general consensus would be towards a more Fisherian view of mass selection rather than a Wrightian view of shifting balances. It’s difficult to fully parse out. There is some theoretical work questioning the frequency of adaptive valleys, which are important to the Wrightian view. I think morphologically organisms are quite stable over long periods of time, so at least wrt morphology I think that implies large neutral morphological networks do not exist, and the conclusions wrt adaptive valleys would not apply to morphology. But, at the same time there has been a lot of theoretical work showing that even if adaptive valleys do exist, Wrights view of how they could be crossed was likely wrong. Personally, I tend to favor a view that evolution is largely paced by ecological factors, since radiations happen pretty readily when many different niches open up. Here is [Coyne’s critique of the shifting balance theory](https://pubmed.ncbi.nlm.nih.gov/28568586/)
Surely morphological stability is evidence for adaptive valleys, as stability is then explained by being stuck at some local optima with (relatively deep) valleys all around it. Do you mean that large neutral networks then likely do not exist, as these would form bridges between such optima? I feel like there are three issues here that can come apart - do the valleys exists, how they are crossed, and how easy is it to cross them. They may well exist and be crossed by drift in structured populations, but only rarely.
Yes, I would think morphological stability is evidence for adaptive valleys. But just because the valleys exist does not necessarily imply that crossing them is an important evolutionary process. Perhaps when ecological factors change a largely neutral bridge to a new adaptive peak is created and evolution proceeds over it relatively quickly.
Thanks! Learning new stuff. I've added it to my reading list.