I've not previously posted about my husband's research, but he's got an amazing new paper out in PLoS Biology being covered by other bloggers too! David Lowry's work demonstrates through experimentation--for the first time in nature--that a chromosomal inversion contributes to adaptation and, in turn, reproductive isolation. In other words, when a section of chromosome flips over it traps adapted genes. By holding these adapted genes prisoner, the reversed chromosomal section then has the fuel it needs to spread across the land. The consequence of its spread is reproductive isolation and potentially a new species.
David's an evolutionary plant geneticist interested in speciation--the environmental and geographic reasons that organisms become two separate species as well as the genetic basis of this process. Why does this matter? When scientists are able to understand adaptive genetic variation within a species, they will be able to do a better job predicting its response to shifting environmental conditions. (Pretty important, given the challenges of limited resources and a changing climate).
David's research over much of the past decade has looked at the heterogeneity of California’s Mediterranean ecosystems. He focused on two ecotypes of the yellow monkeyflower, Mimulus guttatus. One is a coastal perennial (pictured left) version while the other is an annual (pictured right) that's found in inland habitats. David looked at how adaptation to environmental stresses such as drought and salt tolerance leads to reproductive isolating barriers between these annual and perennial types.
And here's the cool part: David has discovered regions of the genome that contribute traits like flowering time, salt tolerance, anthocyanin production, and nutrient uptake between the coastal and inland ecotypes. He spent years crossing numerous individual plants to conduct an experiment that reversed the genetic information for these traits in both lines and then planted them back into coastal and inland habitats in California to test the effects of these gene differences in nature. In this way, he was able to show that the chromosome inversion polymorphism (i.e. reversed chunk of chromosome), which is spread widely over North America, actually causes adaptation and reproductive isolation in nature. While he does not know yet what piece of the inversion is responsible for this pattern, he speculates a number of the over 350 genes stuck in the inversion are involved.
Having watched David toil away in the field and laboratory for years, I am so excited to see this awesome comprehensive articlepublished!
