The molecular basis of human-induced life history adaptation. 01/10/2020 - 30/09/2024

Abstract

We currently lack a detailed understanding of how organisms rapidly adapt to environmental changes. However, gaining such an understanding is key in evaluating and predicting human impact on nature, can uncover the genetic basis of adaptive traits, and give insight into fundamental evolutionary processes. The most direct form of human impact on animal populations is hunting or fishing. Evolutionary responses to fishing have been often discussed, but direct evidence from natural systems is scarce. To address this, we will investigate genetic and phenotypic changes in Malawi cichlid fish following ~40 years of extremely intense fishing. We have recently produced genome sequencing data of 510 individuals of weakly and intensely fished populations from present day and from 18 years ago that will be analysed in this project. Combining this with innovative genome sequencing of museum specimens collected before and during fishing will give unprecedented insight into genes under selection. Furthermore, we will leverage the ease and relative speed of breeding cichlids in the lab to experimentally quantify genetic and environmental differences in traits life history traits implicated in fisheries-induced evolution. Integrating phenotypic measurement with the genomic differentiation measures into a quantitative genetics framework will allow us to directly test whether selection has acted on life history traits. Finally, we will characterise gene expression levels through transcriptome sequencing of tissues important in growth and maturation in weakly and intensely fished populations at different life stages. This will provide insight into adaptation at an important intermediate layer between genotypes and phenotypes. In summary, the combination of genome sequencing of recent and historic natural populations with controlled breeding experiments and transcriptome sequencing will greatly advance our understanding of the link between selective pressures, phenotypes and genotypes and has the potential to uncover how genomes can rapidly adapt to fishing.

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