Many factors can cause populations to diverge genetically (e.g., genetic drift, natural selection, sexual selection). Understanding the relative roles of these factors in generating contemporary population differentiation within and between species can help us understand the generation and maintenance of biodiversity more generally.

Redpoll finch diversity

In collaboration with Nicholas A. Mason, a PhD candidate at the Cornell Lab of Ornithology, I am examining species limits in the redpoll species complex (Acanthis sp.). This species complex has puzzled scientists for decades: the morphological variation exhibited across the circumpolar range of the group is not reflected in the studies of genetic differentiation carried out thus far. Our investigation thus far has used a combination of gene expression, reduced representation genome sequencing, morphological, and niche modeling analyses. Our results indicate that redpolls share a recent evolutionary history (no evidence of long term isolation) and that differential gene expression may be responsible for the morphological variation present within the species. We plan to expand our inquiry in this system with whole genome sequencing,  field studies, and controlled gene expression experiments. The redpolls represent an intriguing group for understanding the drivers of morphological divergence in birds.

Relevant Publications:

Mason NA, Taylor SA2015. Differentially expressed genes match morphology and plumage despite largey homogeneous genomes in a Holarctic songbird. Molecular Ecology 24: 3009 - 3025. PDF

Avian population differentiation

Our population genetics work in other avian systems has (1) found support for the hypothesis that specialization to cold water upwelling systems increases gene flow between seabird colonies, (2) provided genetic information for informing conservation of Caspian terns in North America, and (3) illuminated patterns post-Pelistocene population differentiation in a number of bird species. 

Relevant Publications:

Burg T, Taylor SA, Lemmen K, Gaston AJ, Friesen VL. 2014. Postglacial population differentiation potentially facilitated by a flexible migratory strategy in golden-crowned kinglets (Regulus satrapa). Canadian Journal of Zoology 92: 163-172.  PDF

*Boutilier S, Taylor SA, Morris-Pocock JA, Lavoie R, Friesen VL. 2014. Evidence for genetic differentiation among Caspian tern (Hydroprogne caspia) populations in North America. Conservation Genetics 15: 275-281.  PDF

*Jeyasingham W, Taylor SA, Zavalaga CB, Simeone A, Friesen VL.  2013. Specialization to cold water upwellings facilitates gene flow in seabirds: additional evidence from the Peruvian pelican, Pelecanus thagus (Aves: Pelecanidae). Journal of Avian Biology 44: 297-304.  PDF

Taylor SA, Zavalaga CB, Luna –Jorquera G, Simeone A, Anderson DJ, Friesen VL. 2011. Panmixia and high genetic diversity in a Humboldt Current endemic, the Peruvian Booby (Sula variegata). Journal of Ornithology 152:623-630.  PDF

Taylor SA, *Maclagan L, Anderson DJ, Friesen VL. 2011. Could specialization to cold water upwelling systems influence genetic diversity and gene flow in marine organisms? A case study using the blue-footed booby, Sula nebouxii. Journal of Biogeography 38:883-893.  PDF

+Morris-Pocock JA, +Taylor SA, Birt TP, Damus M, Piatt JF, Warheit KI, Friesen VL. 2008. Population genetic structure in Atlantic and Pacific Ocean common murre (Uria aalge) populations: natural replicate tests of post-Pleistocene evolution. Molecular Ecology 17:4859-4873.  PDF +Both authors contributed equally. 

*Undergraduate ​