Draft genome of six Cuban Anolis lizards and insights into genetic changes during the diversification

Abstract

The detection of various type of genomic variants and their accumulation processes during species diversification and adaptive radiation is important for understanding the molecular and genetic basis of evolution. Anolis lizards in the West Indies are good models for studying the mechanism of the evolution because of the repeated evolution of their morphology and the ecology. In this study, we performed de novo genome assembly of six Cuban Anolis lizards with different ecomorphs and thermal habitats (Anolis isolepis, Anolis allisoni, Anolis porcatus, Anolis allogus, Anolis homolechis, and Anolis sagrei). As a result, we obtained six novel draft genomes with relatively long and high gene completeness, with scaffold N50 ranging from 5.56–39.79 Mb, and vertebrate Benchmarking Universal Single-Copy Orthologs completeness ranging from 77.5% to 86.9%. Subsequently, we performed comparative analysis of genomic contents including those of mainland Anolis lizards to estimate genetic variations that had emerged and accumulated during the diversification of Anolis lizards. Comparing the repeat element compositions and repeat landscapes revealed differences in the accumulation process between Cuban trunk-crown and trunk-ground species, LTR accumulation observed only in A. carolinensis, and separate expansions of several families of LINE in each of Cuban trunk-ground species. The analysis of duplicated genes suggested that the proportional difference of duplicated gene number among Cuban Anolis lizards may be associated to the difference of their habitat range. Furthermore, Pairwise Sequentially Markovian Coalescent analysis proposed that the effective population sizes of each species might have been affected by Cuba’s geohistory. Hence, these six novel draft genome assemblies and detected genetic variations can be a springboard for the further genetic elucidation of the Anolis lizard’s diversification.SignificanceAnolis lizard in the West Indies is excellent model for studying the mechanisms of speciation and adaptive evolution. Still, due to a lack of genome assemblies, genetic variations and accumulation process of them involved in the diversification remain largely unexplored. In this study, we reported the novel genome assemblies of six Cuban Anolis lizards and analyzed evolution of genome contents. From comparative genomic analysis and inferences of genetic variation accumulation process, we detected species- and lineage-specific transposon accumulation processes and gene copy number evolution, considered to be associated with the adaptation to their habitats. Additionally, we estimated past effective population sizes and the results suggested its relationship to Cuba’s geohistory.