University Of Tasmania
Yang et al_MolEcol_2018.pdf (822.84 kB)

Genomic evidence for asymmetric introgression by sexual selection in the common wall lizard

Download (822.84 kB)
journal contribution
posted on 2023-05-19, 21:05 authored by Yang, W, Geoffrey WhileGeoffrey While, Laakkonen, H, Sacchi, R, Zuffi, MAL, Scali, S, Salvi, D, Uller, T
Strongly selected characters can be transferred from one lineage to another with limited genetic exchange, resulting in asymmetric introgression and a mosaic genome in the receiving population. However, systems are rarely sufficiently well studied to link the pattern of introgression to its underlying process. Male common wall lizards in western Italy exhibit exaggeration of a suite of sexually selected characters that make them outcompete males from a distantly related lineage that lack these characters. This results in asymmetric hybridization and adaptive introgression of the suite of characters following secondary contact. We developed genome-wide markers to infer the demographic history of gene flow between different genetic lineages, identify the spread of the sexually selected syndrome, and test the prediction that introgression should be asymmetric and heterogeneous across the genome. Our results show that secondary contact was accompanied by gene flow in both directions across most of the genome, but with approximately 3% of the genome showing highly asymmetric introgression in the predicted direction. Demographic simulations reveal that this asymmetric gene flow is more recent than the initial secondary contact, and the data suggest that the exaggerated male sexual characters originated within the Italian lineage and subsequently spread throughout this lineage before eventually reaching the contact zone. These results demonstrate that sexual selection can cause a suite of characters to spread throughout both closely and distantly related lineages with limited gene flow across the genome at large.


Publication title

Molecular Ecology










School of Natural Sciences


Blackwell Publishing Ltd

Place of publication

9600 Garsington Rd, Oxford, England, Oxon, Ox4 2Dg

Rights statement

© 2018 John Wiley & Sons Ltd. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This is the peer reviewed version which has been published in final form at:

Repository Status

  • Restricted

Socio-economic Objectives

Expanding knowledge in the biological sciences