The effects of historical fragmentation on major histocompatibility complex class II β and microsatellite variation in the Aegean island reptile, Podarcis erhardii

Santonastaso, Trent, Lighten, Jackie, van Oosterhout, Cock, Jones, Kenneth L., Foufopoulos, Johannes and Anthony, Nicola M. (2017) The effects of historical fragmentation on major histocompatibility complex class II β and microsatellite variation in the Aegean island reptile, Podarcis erhardii. Ecology and Evolution, 7 (13). 4568–4581. ISSN 2045-7758

[img]
Preview
PDF (Published manuscript) - Published Version
Available under License Creative Commons Attribution.

Download (943kB) | Preview

Abstract

The major histocompatibility complex (MHC) plays a key role in disease resistance and is the most polymorphic gene region in vertebrates. Although habitat fragmentation is predicted to lead to a loss in MHC variation through drift, the impact of other evolutionary forces may counter this effect. Here we assess the impact of selection, drift, migration, and recombination on MHC class II and microsatellite variability in 14 island populations of the Aegean wall lizard Podarcis erhardii. Lizards were sampled from islands within the Cyclades (Greece) formed by rising sea levels as the last glacial maximum approximately 20,000 before present. Bathymetric data were used to determine the area and age of each island, allowing us to infer the corresponding magnitude and timing of genetic bottlenecks associated with island formation. Both MHC and microsatellite variation were positively associated with island area, supporting the hypothesis that drift governs neutral and adaptive variation in this system. However, MHC but not microsatellite variability declined significantly with island age. This discrepancy is likely due to the fact that microsatellites attain mutation-drift equilibrium more rapidly than MHC. Although we detected signals of balancing selection, recombination and migration, the effects of these evolutionary processes appeared negligible relative to drift. This study demonstrates how land bridge islands can provide novel insights into the impact of historical fragmentation on genetic diversity as well as help disentangle the effects of different evolutionary forces on neutral and adaptive diversity.

Item Type: Article
Uncontrolled Keywords: drift,historical fragmentation,immunity,major histocompatibility complex,selection
Faculty \ School: Faculty of Science > School of Environmental Sciences
Related URLs:
Depositing User: Pure Connector
Date Deposited: 24 May 2017 05:04
Last Modified: 19 Sep 2019 00:20
URI: https://ueaeprints.uea.ac.uk/id/eprint/63598
DOI: 10.1002/ece3.3022

Actions (login required)

View Item View Item