Besides their role as a model system in speciation research, Lake Malawi cichlids are food for millions of people, and subject to a recent and strong increase in fishing. Some cichlid populations have seemingly adapted their life histories to high fishing pressure and mature at substantially smaller size compared to less heavily fished populations. In this project, we will dissect the genetic factors contributing to rapid phenotypic adaptation in Lake Malawi cichlid fish populations following ~40 years of extremely heavy fishing.
Fisheries-induced adaptation (FIA) in Lake Malawi cichlids provides an ideal system to study rapid adaptation, because of
- extensive genomic resources currently becoming available for Lake Malawi cichlids will allow us to cost-effectively sequence and compare the genomes of weakly and heavily fished populations
- > 2000 already existing Malawi cichlid whole-genome sequences of 270 species will allow us to infer the long-term evolutionary history of genetic variants used in recent adaptation to heavy fishing
- analysing population genome data from museum specimen from before and during heavy fishing, will give unprecedented insight into the selective process across time
breeding cichlids in the lab will allow us to
- experimentally quantify genetic (as opposed to environmental) differences in traits implicated in fisheries-induced adaptation
- map the genetic variants contributing to within and between-population variation in traits using association mapping and crosses.
In summary, the combination of genome sequencing of recent and historic natural populations with controlled breeding experiments will greatly advance our understanding of the link between selection pressures, phenotypes and genotypes, will enable the dissection of complex traits, and will uncover how genomes can rapidly adapt to human-induced selection.