Genomic implications of severe population bottlenecks in two Mustelid species

Shaw, Rebecca Lianne (2025) Genomic implications of severe population bottlenecks in two Mustelid species. Doctoral thesis, University of East Anglia.

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Abstract

The accelerating decline in global biodiversity is now recognised as a sixth mass extinction event, representing an unprecedented ecological crisis. Habitat destruction, climate change, direct persecution and overexploitation of natural resources have rendered animal populations increasingly susceptible to decline, with 73% of the 5,495 vertebrate populations monitored by the IUCN Red List exhibiting reductions over the past five decades. Population bottlenecks, a common consequence of such pressures, reduce genetic diversity, increase inbreeding and can compromise long-term viability, yet their genomic consequences vary in magnitude and persistence. This thesis examines these impacts in two mustelids that experienced markedly different bottlenecks: the European polecat (Mustela putorius) and the black-footed ferret (Mustela nigripes). In Chapter Two, I used whole-genome data from British and mainland European polecats to investigate population structure, diversity and demographic history. The British population showed genetic isolation from the continent, with Welsh polecats distinct from English ones. A nineteenth-century bottleneck in Wales was detected, less severe than that of the black-footed ferret, accompanied by evidence of recent inbreeding. In Chapter Three, I examined coding-region variation in the black-footed ferret using historic, captive and reintroduced genomes. The extreme twentieth-century bottleneck caused substantial diversity loss, fixation of some deleterious alleles and elevated mutational load. In Chapter Four, I extended this to conserved non-coding elements, identifying regulatory variants near genes involved in reproduction, neurodevelopment and immunity, some predicted to alter transcription factor binding and potentially contributing to reduced fertility. I synthesise these findings in a broader conservation genomic context, showing how differences in bottleneck severity and duration influence the retention of diversity and accumulation of deleterious mutations, with implications for the management of small or recovering carnivore populations.

Item Type:	Thesis (Doctoral)
Faculty \ School:	Faculty of Science > School of Biological Sciences
Depositing User:	Chris White
Date Deposited:	18 May 2026 10:24
Last Modified:	18 May 2026 10:24
URI:	https://ueaeprints.uea.ac.uk/id/eprint/103063
DOI:

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