ECOLOGICAL GENOMICS: The genomic landscape... : Science (original) (raw)

ECOLOGICAL GENOMICS: The genomic landscape underlying phenotypic integrity in the face of gene flow in crows

• J. W. Poelstra
• N. Vijay
• C. M. Bossu
• H. Lantz
• B. Ryll
• I. Müller
• V. Baglione
• P. Unneberg
• M. Wikelski
• M. G. Grabherr
• J. B. W. Wolf

Science

344

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6190

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:p

1410

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1414

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June 20, 2014

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| DOI: 10.1126/science.1253226

The importance, extent, and mode of interspecific gene flow for the evolution of species has long been debated. Characterization of genomic differentiation in a classic example of hybridization between all-black carrion crows and gray-coated hooded crows identified genome-wide introgression extending far beyond the morphological hybrid zone. Gene expression divergence was concentrated in pigmentation genes expressed in gray versus black feather follicles. Only a small number of narrow genomic islands exhibited resistance to gene flow. One prominent genomic region (<2 megabases) harbored 81 of all 82 fixed differences (of 8.4 million single-nucleotide polymorphisms in total) linking genes involved in pigmentation and in visual perception—a genomic signal reflecting color-mediated prezygotic isolation. Thus, localized genomic selection can cause marked heterogeneity in introgression landscapes while maintaining phenotypic divergence.