Genomic basis of adaptation in avian systems

Abstract

Despite much work investigating the evolutionary causes and the neural mechanisms controlling complex social behaviours, the genetic mechanisms behind these behaviours are still poorly understood.

In this thesis, I have applied a mixture of transcriptomic, genomic and traditional genetic techniques to explore the evolution and genetic mechanisms controlling social behaviour and other complex phenotypes. My work has produced several major results.

Firstly, using a model system of small plovers (genus Charadrius), I found no evidence to support two major hypotheses that relatedness or temporal patterns influence extra-pair paternity. Instead, I suggest that extra-pair paternity is low in plovers due to social constraints.

Secondly, using genomic resources, I present work examining the divergence in two closely related species of plover located in China. I found evidence of low levels of divergence and selection across the genome, although a few genes were highly differentiated. I also present evidence of differences in the demographic histories of the two plover species which occurred during the Last Glaciation Period.

Thirdly, I found large differences in sex-biased gene expression between four social brain regions from incubating Kentish plovers (Charadrius alexandrinus). The hypothalamus, a region of known importance for incubation behaviour, was the most dimorphic region. Fourthly, I investigated the genetic mechanisms of parental care by comparing gene expression differences in caring and non-caring captive zebra finches. I found small differences in gene expression patterns in the hypothalamus.

Finally, I investigated the effect of sexual selection on the brain transcriptome. I identified genes which correlate with sexual size dimorphism in the mammalian brain. The work presented in this thesis contributes substantially to improving our understanding of complex social behaviours and complex traits. It also highlights the benefit of integrating the independent fields of behavioural ecology, neuroscience and comparative genomics for advancing our knowledge in this area.

Date of Award	1 May 2019
Original language	English
Awarding Institution	University of Bath
Supervisor	Araxi Urrutia (Supervisor) & Tamas Szekely (Supervisor)