Isolation by environment explains why the grass isn’t always greener

Ever since Sewall Wright introduced isolation by distance in 1943, the interplay between genetic differentiation and geographic distance has been a foundational, sometimes frustrating, aspect of population genetics studies.

But distance isn’t just distance. The walk to my car isn’t any longer when rain is pouring down, but it sure feels that way.

Isolation by environment (IBE) is a”pattern in which genetic differentiation increases with environmental differences, independent of geographic distance.” A timely review by Dr. Ian Wang and Gideon Bradburd provides a current perspective on IBE and how considering both environmental and geographic distance can lead to more impactful inferences.

The rise of IBE as a research focus has resulted in a tremendous opportunity to examine, often at very fine scales, the ways in which ecology shapes genetic variation in nature, forming a true bridge between the fields of population genetics and landscape ecology.

Wang and Bradburd not only discuss current software (such as BEDASSLE) used to recognize patterns of IBE, but also offer up some of the potential processes that generate those patterns, like sexual selection against immigrants and biased dispersal.

Isolation by environment will play a major part in the next big steps, providing a framework for examining how ecological and environmental heterogeneity shape the distribution of genetic variation in nature.

Also, don’t forget to check the article’s supplementary material for an animated GIF used to describe the relationship between genetic, environment, and geographic distance.

Is it the same information as a figure in the article? Yes.

Are animated graphs cool? You bet.

 

Wang I.J. & Bradburd G.S. (2014). Isolation by environment, Molecular Ecology, 23 (23) 5649-5662. DOI: http://dx.doi.org/10.1111/mec.12938

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About Rob Denton

I'm a Postdoctoral Fellow in the Department of Molecular and Cell Biology at UConn. I'm most interested in understanding the evolutionary/ecological consequences of strange reproduction in salamanders (unisexual Ambystoma). Topics I'm likely to write about: population and landscape genetics, mitonuclear interactions, polyploidy, and reptiles/amphibians.
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