Selection and gene flow shape genomic islands that control floral guides
| Autor: | Alexandra B. Rebocho, David L. Field, Desmond Bradley, Miaomiao Li, Joane Elleouet, Christophe Andalo, Qun Li, Monique Burrus, Enrico Coen, Annabel Whibley, Hugo Tavares, Lucy Copsey, Nicolas H. Barton, Yongbiao Xue, Matthew Couchman |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Gene Flow
0106 biological sciences 0301 basic medicine Genomic Islands Evolution Genetic Speciation Color Flowers Biology 010603 evolutionary biology 01 natural sciences Chromosomes Plant Gene flow Divergence selective sweep 03 medical and health sciences genomic island Antirrhinum majus Hybrid zone Genomic island Antirrhinum Selection Genetic Multidisciplinary fungi food and beverages Reproductive isolation Biological Sciences 15. Life on land biology.organism_classification 030104 developmental biology speciation Evolutionary biology hybrid zone Selective sweep Genome Plant |
| Zdroj: | Proceedings of the National Academy of Sciences of the United States of America |
| ISSN: | 1091-6490 0027-8424 |
| Popis: | Significance Populations often show “islands of divergence” in the genome. Analysis of divergence between subspecies of Antirrhinum that differ in flower color patterns shows that sharp peaks in relative divergence occur at two causal loci. The island is shaped by a combination of gene flow and multiple selective sweeps, showing how divergence and barriers between populations can arise and be maintained. 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 majus, 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. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|