The effects of climate and demographic history in shaping genomic variation across populations of the Desert Horned Lizard (Phrynosoma platyrhinos)

<p>Species often experience spatial <span class="NormalTextRun SCXW235808685 BCX2">environmental </span><span class="NormalTextRun SCXW235808685 BCX2">heterogeneity </span><span class="NormalTextRun SCXW235808685 BCX2">across their range</span><span class="NormalTextRun SCXW235808685 BCX2">, </span><span class="NormalTextRun SCXW235808685 BCX2">and </span><span class="NormalTextRun SCXW235808685 BCX2">populations </span><span class="NormalTextRun SCXW235808685 BCX2">may exhibit </span><span class="NormalTextRun SCXW235808685 BCX2">signatures </span><span class="NormalTextRun SCXW235808685 BCX2">of adaptation to local environmental </span><span class="NormalTextRun SCXW235808685 BCX2">characteristics.</span><span class="NormalTextRun SCXW235808685 BCX2"> Other population</span><span class="NormalTextRun SCXW235808685 BCX2"> genetic</span><span class="NormalTextRun SCXW235808685 BCX2"> processes, </span><span class="NormalTextRun SCXW235808685 BCX2">such as </span><span class="NormalTextRun SCXW235808685 BCX2">migration and genetic drift, </span><span class="NormalTextRun SCXW235808685 BCX2">can </span><span class="NormalTextRun SCXW235808685 BCX2">impede the effect</span><span class="NormalTextRun SCXW235808685 BCX2">s</span><span class="NormalTextRun SCXW235808685 BCX2"> of </span><span class="NormalTextRun SCXW235808685 BCX2">local adaptation</span><span class="NormalTextRun SCXW235808685 BCX2">. Genetic drift </span><span class="NormalTextRun SCXW235808685 BCX2">in particular </span><span class="NormalTextRun SCXW235808685 BCX2">can have a pronounced effect on population genetic structure during large-scale geographic expansions, where a series of founder effects lead</span><span class="NormalTextRun SCXW235808685 BCX2">s</span><span class="NormalTextRun SCXW235808685 BCX2"> to decreases in genetic variation in the direction of the expansion. </span><span class="NormalTextRun SCXW235808685 BCX2">Here </span><span class="NormalTextRun SCXW235808685 BCX2">we explore the </span><span class="NormalTextRun SCXW235808685 BCX2">genetic diversity</span><span class="NormalTextRun SCXW235808685 BCX2"> of a desert lizard that occupies a wide range of environmental conditions and that has experienced post-glacial expansion northwards along two colonization routes. </span><span class="NormalTextRun SCXW235808685 BCX2">Based on our analyses of a large SNP dataset, we find evidence </span><span class="NormalTextRun SCXW235808685 BCX2">that both </span><span class="NormalTextRun SCXW235808685 BCX2">climate and demographic history</span><span class="NormalTextRun SCXW235808685 BCX2"> </span><span class="NormalTextRun SCXW235808685 BCX2">have </span><span class="NormalTextRun SCXW235808685 BCX2">shape</span><span class="NormalTextRun SCXW235808685 BCX2">d</span><span class="NormalTextRun SCXW235808685 BCX2"> the </span><span class="NormalTextRun SCXW235808685 BCX2">genetic</span><span class="NormalTextRun SCXW235808685 BCX2"> structure of</span><span class="NormalTextRun SCXW235808685 BCX2"> populations. </span><span class="NormalTextRun SCXW235808685 BCX2">P</span><span class="NormalTextRun SCXW235808685 BCX2">ronounced genetic differentiation</span><span class="NormalTextRun SCXW235808685 BCX2"> was evident </span><span class="NormalTextRun SCXW235808685 BCX2">between populations occupying cold versus hot desert</span><span class="NormalTextRun SCXW235808685 BCX2">s</span><span class="NormalTextRun SCXW235808685 BCX2">,</span><span class="NormalTextRun SCXW235808685 BCX2"> and </span><span class="NormalTextRun SCXW235808685 BCX2">we </span><span class="NormalTextRun SCXW235808685 BCX2">detected numerous loci </span><span class="NormalTextRun SCXW235808685 BCX2">with </span><span class="NormalTextRun SCXW235808685 BCX2">significant association</span><span class="NormalTextRun SCXW235808685 BCX2">s</span><span class="NormalTextRun SCXW235808685 BCX2"> with climate. The genetic signal of founder effect</span><span class="NormalTextRun SCXW235808685 BCX2">s</span><span class="NormalTextRun SCXW235808685 BCX2">, however, is still present in the genomes of the recently expanded populations</span><span class="NormalTextRun SCXW235808685 BCX2">, </span><span class="NormalTextRun SCXW235808685 BCX2">which</span><span class="NormalTextRun SCXW235808685 BCX2"> comprise subsets of genetic variation found in the southern populations, and </span><span class="NormalTextRun SCXW235808685 BCX2">we found substantial evidence that </span><span class="NormalTextRun SCXW235808685 BCX2">genetic diversity of lizards differs along the two colonization routes.</span></p>