Project description:Genomes of closely-related species or populations often display localized regions of enhanced relative sequence divergence, termed genomic islands. It has been proposed that these islands arise through selective sweeps and/or barriers to gene flow. Here, we genetically dissect a genomic island that controls flower color pattern differences between two subspecies of Antirrhinum, A.m.striatum and A.m.pseudomajus, and relate it to clinal variation across a natural hybrid zone. We show that selective sweeps likely raised relative divergence at two tightly-linked MYB-like transcription factors, leading to distinct flower patterns in the two subspecies. The two patterns provide alternate floral guides and create a strong barrier to gene flow where populations come into contact. This barrier affects the selected flower color genes and tightly linked loci, but does not extend outside of this domain, allowing gene flow to lower relative divergence for the rest of the chromosome. Thus, both selective sweeps and barriers to gene flow play a role in shaping genomic islands: sweeps cause elevation in relative divergence while heterogeneous gene flow flattens the surrounding “sea”, making the island of divergence stand out. By showing how selective sweeps establish alternative adaptive phenotypes that lead to barriers to gene flow, our study sheds light on possible mechanisms leading to reproductive isolation and speciation.
2018-08-18 | GSE118621 | GEO
Project description:Euphrasia contact zone genotyping by sequencing
Project description:Arabidopsis thaliana plants were grown from seeds in Petri dishes on MS medium. 4 days old plants were co-incubated with L. bicolor without physical contact. After 2 days of co-incubation, roots were either harvested whole or separated into the root tip (ca. 1/4 of the whole root) and the lateral root zone (= remaining root).
Project description:We describe a more detailed survey undertaken to detect candidate CNVs in a panel of 20 Asian cultivated rice and the genome-wide characteristics of CNVs in subspecies and groups. These resources allowed us to analyze genetic structure as indicated by CNVs, to implicate the biological roles of CNVs, and to identify candidate CNVs that are likely to occur independently in groups and contribute to differences between the subspecies.
