Population Differentiation, Historical Demography and Evolutionary Relationships Among Widespread Common Chaffinch Populations (Fringilla coelebs ssp.)

• Main Author: Samarasin-Dissanayake, Pasan
• Other Authors: Baker, Allan J.
• Language: en_ca
• Published: 2010
• Subjects: coalescent theory; population structure; colonization; demographic history; Bayesian methods; incomplete lineage sorting; species trees; 0472
• Online Access: http://hdl.handle.net/1807/24633

Widespread species that occupy continents and oceanic islands provide an excellent opportunity to study evolutionary forces responsible for population divergence. Here, I use multilocus coalescent based population genetic and phylogenetic methods to infer the evolutionary history of the common chaffinch (Fringilla coelebs), a widespread Palearctic passerine species. My results showed strong population structure between Atlantic islands. However, the two European subspecies can be considered one panmictic population based on gene flow estimates. My investigation of effects of sampling on concatenated and Bayesian estimation of species tree (BEST) methods demonstrated that concatenation is more sensitive to sampling than BEST. Furthermore, concatenation can provide incorrect evolutionary relationships with high confidence when sample size is small. In conclusion, my results suggest European ancestry for the common chaffinch and Atlantic islands appear to have been colonized sequentially from north to south via Azores.