Rapid, nonparallel genomic evolution of Brassica rapa (field mustard) under experimental drought

Abstract

Rapid evolution to environmental conditions has been documented by a number of studies (Franks et al., 2014;Hendry & Kinnison, 1999). However, the genomic basis of rapid evolution is less often characterized yet is fundamentally important as it can allow identification of adaptive loci and possible genetic pathways that increase fitness (Franks & Hoffmann, 2012). Studies that explore the genomic basis of rapid adaptation often find changes in many polymorphic loci. For example, adaptation to climate has been tied to subtle shifts in allele frequencies across many loci in the thale cress A. thaliana (Hancock et al., 2011), the stickleback G. aculeatus (Roberts Kingman et al., 2021), and the mouse M. musculus (Ferris et al., 2021). These examples suggest that rapid adaptation may often occur through changes in standing variation (Messer & Petrov, 2013;Pritchard et al., 2010).While progress has been made toward understanding the genomic basis of rapid adaptation, less is known about the consistency of genomic shifts underlying rapid evolution (Blount et al., 2018;Lobkovsky & Koonin, 2012). If rapid evolution is driven by selection, genetically similar populations under the same environment are likely to evolve similar outcomes (parallel evolution). However,

Adaptive radiation of the Callicarpa genus in the Bonin Islands revealed through double-digest restriction site–associated DNA sequencing analysis

“…Examples of organisms rapidly altering their phenotypes upon aridification have been reported in animals, such as Darwin's finches (Grant & Grant, 2006), and in plants, such as Mimulus andBrassica (Dickman et al, 2019;Johnson et al, 2022). Selection has also been observed on the HMGA2 gene, causing beak size variation during drought in Darwin's finches (Lamichhaney et al, 2016), and multiple genes associated with drought response traits evolving during drought in Brassica (Franks et al, 2016;Johnson et al, 2023). In the Callicarpa genus in the Bonin Islands, rapid adaptation to aridification may have led to speciation.…”

Transposable elements identify previously overlooked regions undergoing parallel evolution in response to diverse selective pressures

“…While Drosophila continues to be a premier system for E&R studies, the range of organisms in which this experimental approach has been successfully applied continues to increase and includes diverse organisms, such as bacteria, yeast, plants and nematodes, among others ( e.g. Burghardt, et al 2018; Phillips, et al 2020; Johnson, et al 2023; Eoche-Bosy, et al 2017).…”