Hybrid Zones | Windows on evolution
Chickadee Hybridization:
Black-capped (Poecile atricapillus) and Carolina chickadees (P. carolinensis) hybridize in a narrow band that stretches from New Jersey to Kansas. Using a combination of genomic, transcriptomic, and citizen science approaches we are investigating (1) the genomic architecture of reproductive isolation between chickadees and (2) the extent and mechanism of movement of this hybrid zone over the past decade.
Thus far, we have found (1) that genomic signatures of reproductive isolation between chickadees are consistent through time and may be related to physiological differences between the species and (2) that the chickadee hybrid zone has moved rapidly north over the past decade in response to climate change.
We are currently following this work up with comparative transcriptomics, mitochondrial enzyme activity assays, and whole mitochondria respiration studies.
This research is being carried out in collaboration with Robert Curry (Villanova University), Zac Cheviron (University of Illinois), and Matt Carling (University of Wyoming).
Relevant Publications:
Taylor SA, Curry RL, White TA, Ferretti V, Lovette I. 2014. Spatiotemporally consistent genomic signatures of reproductive isolation in a moving hybrid zone. Evolution 68: 3066-3081.
Taylor SA, White TA, Hochachka WM, Ferretti V, Curry RL, Lovette I. 2014. Climate Mediated Movement of an Avian Hybrid Zone. Current Biology 24: 671-676.
Perspective: Harr B, Price T. 2014. Climate Change: A Hybrid Zone Moves North. Current Biology 24: 230-232
Warbler Hybridization:
Golden-winged and blue-winged warblers hybridize extensivly where their ranges overlap in eastern North America. Though phenotypically very different, traditional genetic markers have failed to provide insight into species-level differences. In collaboration with colleagues at the Cornell Lab of Ornithology we used whole-genome sequencing to investgate patterns of genomic divergence between the two species. Our results revealed that golden-winged and blue-winged warbler genomes differ very little, and those sites that do differ tend to fall directly upstream of genes with clear connections to feather patterning and coloration.
Relevant Publications:
+Toews DPL, +Taylor SA, Vallender R, Brelsford A, Butcher BG, Messer PW, Lovette IJ. 2016. Plumage genes and little else distinguish the genomes of hybridizing warblers. Current Biology. In Press. +Authors contributed equally.
Booby Hybridization:
Blue-footed (Sula nebouxii) and Peruvian boobies (S. variegate) hybridize on two islands in northern Peru, at the northern extent of the Humboldt current upwelling system. We investigated hybridization in this system using a combination of mitochondrial sequence data and a panel of 18 microsatellites. Hybridization between blue-footed and Peruvian boobies is unidirectional: female Peruvian boobies will mate with male blue-footed boobies, but female blue-footed boobies do not appear to mate with male Peruvian boobies. This asymmetry may be caused by foot color, which is under sexual selection in boobies.
Relevant Publications:
Taylor SA, Anderson DJ, Friesen VL. 2013. Evidence for asymmetrical gene flow of nuclear loci, but not mitochondrial loci, between a seabird species pair. PLoS ONE. 8(4): e62256.
Taylor SA, Friesen VL. 2012. Evidence for strong assortative mating, limited gene flow, and strong differentiation across the blue-footed / Peruvian booby hybrid zone in northern Peru. Journal of Avian Biology 43: 311-324.
Taylor SA, Zavalaga CB, Friesen VL. 2010. Hybridization between blue-footed (Sula nebouxii) and Peruvian (S. variegata) boobies in northern Peru. Waterbirds 33: 251-257.
Murre Hybridization:
Common (Uria aalge) and thick-billed murres (U. lomvia) are closely related seabirds of the northern hemisphere that are morphologically similar and breed in dense colonies. We investigated hybridization between common and thick-billed murres in the north Pacific using a combination of nuclear and mitochondrial loci and found evidence of cryptic introgression. This was the first genetic evidence of murre hybridization and has implications for the conservation of thick-billed murres, which are arctic specialists.
Relevant Publications:
Taylor SA, Patirana A, Birt T, Piatt J, Friesen VL. 2012. Cryptic introgression between murre sister species (Uria spp.) in the Pacific low Arctic: frequency, cause, and implications. Polar Biology. 35: 931-940.