Strong premating reproductive isolation drives incipient speciation in Mimulus aurantiacus.

Autor: Sobel JM; Department of Biological Sciences, Binghamton University, State University of New York, Binghamton, New York, 13902., Streisfeld MA
Jazyk: angličtina
Zdroj: Evolution; international journal of organic evolution [Evolution] 2015 Feb; Vol. 69 (2), pp. 447-61. Date of Electronic Publication: 2015 Jan 20.
DOI: 10.1111/evo.12589
Abstrakt: Determining which forms of reproductive isolation have the biggest impact on the process of divergence is a major goal of speciation research. These barriers are often divided into those that affect the potential for hybridization (premating isolation), and those that occur after mating (postmating isolation), and much debate has surrounded the relative importance of these categories. Within the species Mimulus aurantiacus, red- and yellow-flowered ecotypes occur in the southwest corner of California, and a hybrid zone occurs where their ranges overlap. We show that premating barriers are exclusively responsible for isolation in this system, with both ecogeographic and pollinator isolation contributing significantly to total isolation. Postmating forms of reproductive isolation have little or no impact on gene flow, indicating that hybrids likely contribute to introgression at neutral loci. Analysis of molecular variation across thousands of restriction-site associated DNA sequencing (RAD-seq) markers reveals that the genomes of these taxa are largely undifferentiated. However, structure analysis shows that these taxa are distinguishable genetically, likely due to the impact of loci underlying differentiated adaptive phenotypes. These data exhibit the power of divergent natural selection to maintain highly differentiated phenotypes in the face of gene flow during the early stages of speciation.
(© 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.)
Databáze: MEDLINE
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