Effect of population size and selection on Toll-like receptor diversity in populations of Galapagos mockingbirds

0567728 - BC 2024 RIV GB eng J - Journal Article
Vlček, Jakub - Miláček, Matěj - Vinkler, M. - Štefka, Jan
Effect of population size and selection on Toll-like receptor diversity in populations of Galapagos mockingbirds.
Journal of Evolutionary Biology. Roč. 36, č. 1 (2023), s. 109-120. ISSN 1010-061X. E-ISSN 1420-9101
Institutional support: RVO:60077344
Keywords : conservation genetics * innate immunity * island birds * molecular phenotype * purifying selection
OECD category: Veterinary science
Impact factor: 2.1, year: 2022
Method of publishing: Limited access
https://onlinelibrary.wiley.com/doi/10.1111/jeb.14121

The interactions of evolutionary forces are difficult to analyse in free-living populations. However, when properly understood, they provide valuable insights into evolutionary biology and conservation genetics. This is particularly important for the interplay of genetic drift and natural selection in immune genes that confer resistance to disease. The Galapagos Islands are inhabited by four closely related species of mockingbirds (Mimus spp.). We used 12 different-sized populations of Galapagos mockingbirds and one population of their continental relative northern mockingbird (Mimus polyglottos) to study the effects of genetic drift on the molecular evolution of immune genes, the Toll-like receptors (TLRs: TLR1B, TLR4 and TLR15). We found that neutral genetic diversity was positively correlated with island size, indicating an important effect of genetic drift. However, for TLR1B and TLR4, there was little correlation between functional (e.g., protein) diversity and island size, and protein structural properties were largely conserved, indicating only a limited effect of genetic drift on molecular phenotype. By contrast, TLR15 was less conserved and even its putative functional polymorphism correlated with island size. The patterns observed for the three genes suggest that genetic drift does not necessarily dominate selection even in relatively small populations, but that the final outcome depends on the degree of selection constraint that is specific for each TLR locus.
Permanent Link: https://hdl.handle.net/11104/0340931