Tags

Type your tag names separated by a space and hit enter

Cross-decades stability of an avian hybrid zone.
J Evol Biol. 2019 11; 32(11):1242-1251.JE

Abstract

Hybrid zones are particularly valuable for understanding the evolution of partial reproductive isolation between differentiated populations. An increasing number of hybrid zones have been inferred to move over time, but in most such cases zone movement has not been tested with long-term genomic data. The hybrid zone between Townsend's Warblers (Setophaga townsendi) and Hermit Warblers (S. occidentalis) in the Washington Cascades was previously inferred to be moving from northern S. townsendi southwards towards S. occidentalis, based on plumage and behavioural patterns as well as a 2000-km genetic wake of hermit mitochondrial DNA (mtDNA) in coastal Townsend's Warblers. We directly tested whether hybrid zone position has changed over 2-3 decades by tracking plumage, mtDNA and nuclear genomic variation across the hybrid zone over two sampling periods (1987-94 and 2015-16). Surprisingly, there was no significant movement in genomic or plumage cline centres between the two time periods. Plumage cline widths were narrower than expected by neutral diffusion, consistent with a 'tension zone' model, in which selection against hybrids is balanced by movement of parental forms into the zone. Our results indicate that this hybrid zone is either stable in its location or moving at a rate that is not detectable over 2-3 decades. Despite considerable gene flow, the stable clines in multiple phenotypic and genotypic characters over decades suggest evolutionary stability of this young pair of sister species, allowing divergence to continue. We propose a novel biogeographic scenario to explain these patterns: rather than the hybrid zone having moved thousands of kilometres to its current position, inland Townsend's met coastal Hermit Warbler populations along a broad front of the British Columbia and Alaska coast and hybridization led to replacement of the Hermit Warbler plumage with Townsend's Warbler plumage patterns along this coastline. Hence, hybrid zones along British Columbia and Alaska moved only a short distance from the inland to the coast, whereas the Hermit Warbler phenotype appears stable in Washington and further south. This case provides an example of the complex biogeographic processes that have led to the distribution of current phenotypes within and among closely related species.

Authors+Show Affiliations

Department of Zoology, University of British Columbia, Vancouver, BC, Canada.Department of Biology and Burke Museum, University of Washington, Seattle, WA, USA.Department of Biology, Texas A & M, College Station, TX, USA.Department of Zoology, University of British Columbia, Vancouver, BC, Canada.

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

31430391

Citation

Wang, Silu, et al. "Cross-decades Stability of an Avian Hybrid Zone." Journal of Evolutionary Biology, vol. 32, no. 11, 2019, pp. 1242-1251.
Wang S, Rohwer S, Delmore K, et al. Cross-decades stability of an avian hybrid zone. J Evol Biol. 2019;32(11):1242-1251.
Wang, S., Rohwer, S., Delmore, K., & Irwin, D. E. (2019). Cross-decades stability of an avian hybrid zone. Journal of Evolutionary Biology, 32(11), 1242-1251. https://doi.org/10.1111/jeb.13524
Wang S, et al. Cross-decades Stability of an Avian Hybrid Zone. J Evol Biol. 2019;32(11):1242-1251. PubMed PMID: 31430391.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Cross-decades stability of an avian hybrid zone. AU - Wang,Silu, AU - Rohwer,Sievert, AU - Delmore,Kira, AU - Irwin,Darren E, Y1 - 2019/10/03/ PY - 2019/06/06/received PY - 2019/08/06/revised PY - 2019/08/13/accepted PY - 2019/8/21/pubmed PY - 2019/8/21/medline PY - 2019/8/21/entrez KW - Setophaga KW - cline KW - hybrid zone KW - hybrid zone movement KW - speciation KW - tension zone SP - 1242 EP - 1251 JF - Journal of evolutionary biology JO - J. Evol. Biol. VL - 32 IS - 11 N2 - Hybrid zones are particularly valuable for understanding the evolution of partial reproductive isolation between differentiated populations. An increasing number of hybrid zones have been inferred to move over time, but in most such cases zone movement has not been tested with long-term genomic data. The hybrid zone between Townsend's Warblers (Setophaga townsendi) and Hermit Warblers (S. occidentalis) in the Washington Cascades was previously inferred to be moving from northern S. townsendi southwards towards S. occidentalis, based on plumage and behavioural patterns as well as a 2000-km genetic wake of hermit mitochondrial DNA (mtDNA) in coastal Townsend's Warblers. We directly tested whether hybrid zone position has changed over 2-3 decades by tracking plumage, mtDNA and nuclear genomic variation across the hybrid zone over two sampling periods (1987-94 and 2015-16). Surprisingly, there was no significant movement in genomic or plumage cline centres between the two time periods. Plumage cline widths were narrower than expected by neutral diffusion, consistent with a 'tension zone' model, in which selection against hybrids is balanced by movement of parental forms into the zone. Our results indicate that this hybrid zone is either stable in its location or moving at a rate that is not detectable over 2-3 decades. Despite considerable gene flow, the stable clines in multiple phenotypic and genotypic characters over decades suggest evolutionary stability of this young pair of sister species, allowing divergence to continue. We propose a novel biogeographic scenario to explain these patterns: rather than the hybrid zone having moved thousands of kilometres to its current position, inland Townsend's met coastal Hermit Warbler populations along a broad front of the British Columbia and Alaska coast and hybridization led to replacement of the Hermit Warbler plumage with Townsend's Warbler plumage patterns along this coastline. Hence, hybrid zones along British Columbia and Alaska moved only a short distance from the inland to the coast, whereas the Hermit Warbler phenotype appears stable in Washington and further south. This case provides an example of the complex biogeographic processes that have led to the distribution of current phenotypes within and among closely related species. SN - 1420-9101 UR - https://www.unboundmedicine.com/medline/citation/31430391/Cross_decades_stability_of_an_avian_hybrid_zone_ L2 - https://doi.org/10.1111/jeb.13524 DB - PRIME DP - Unbound Medicine ER -
Try the Free App:
Prime PubMed app for iOS iPhone iPad
Prime PubMed app for Android
Prime PubMed is provided
free to individuals by:
Unbound Medicine.