Recent nonhybrid origin of sunflower ecotypes in a novel habitat.

摘要: The genomics of local adaptation is an increasingly active field, providing insights into the forces driving ecological speciation and repeatability evolution. Demography gene flow play important role in determining paths by which parallel evolution occurs genomic signatures adaptation. In annual sunflowers, hybridization between species has repeatedly led to colonization extreme habitats, such as sand dunes. a new case dunes that populations H. petiolaris growing at Great Sand Dunes National Park Preserve (Colorado), we wished determine age long-term migration patterns system, well its ancestry. We addressed these questions with restriction-associated DNA (RAD) sequence data, aligned reference transcriptome. isolation model using RAD sequences, coalescent analysis showed dune ecotype originated since last ice age, very recent compared hybrid species, anomalus. Large effective population sizes substantial numbers migrants per generation nondune ecotypes explained highly heterogeneous divergence observed among loci. Analysis RAD-derived SNPs identified ecotypes, identifying nearest relative. Our results did not support hypothesis ancestry, suggesting sunflowers occurred multiple mechanisms. ancestry history incipient sunflower provides valuable context for our understanding