ORCID Profile
0000-0003-1533-2430
Current Organisation
University of Basel
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Publisher: Cold Spring Harbor Laboratory
Date: 13-01-2021
DOI: 10.1101/2021.01.12.426414
Abstract: Understanding the drivers and dynamics of ersification is a central topic in evolutionary biology. Here, we investigated the dynamics of ersification in the cichlid fish Astatotilapia burtoni that erged along a lake-stream environmental gradient. Whole-genome and morphometric analyses revealed that ergent selection was essential at the early stages of ersification, but that periods in allopatry were likely involved towards the completion of speciation. While morphological differentiation was continuous, genomic differentiation was not, as shown by two clearly separated categories of genomic differentiation. Reproductive isolation increased along a continuum of genomic ergence, with a “grey zone” of speciation at ∼0.1% net nucleotide ergence. The quantification of the extent of (non-)parallelism in nine lake-stream population pairs from four cichlid species by means of multivariate analyses revealed one parallel axis of genomic and morphological differentiation among seven lake-stream systems. Finally, we found that parallelism was higher when ancestral lake populations were more similar.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 05-11-2021
Abstract: African cichlid fishes reveal the dynamics of speciation and the predictability of evolution.
Publisher: Wiley
Date: 07-10-2018
DOI: 10.1111/EVO.13612
Abstract: Understanding how reproductive barriers evolve and which barriers contribute to speciation requires the examination of organismal lineages that are still in the process of ersification and the study of the full range of reproductive barriers acting at different life stages. Lake and river ecotypes of the East African cichlid fish Astatotilapia burtoni show habitat-specific adaptations, despite different levels of genetic differentiation, and thus represent an ideal model to study the evolution of reproductive barriers. To evaluate the degree of reproductive isolation between genetically ergent lake and river populations, we performed a mesocosm mating experiment in a semi-natural setting at Lake Tanganyika. We assessed reproductive isolation in the presence of male-male competition by analyzing survival and growth rates of introduced adults and their reproductive success from genetic parentage of surviving offspring. The genetically ergent river population showed reduced fitness in terms of survival, growth rate, and mating success in a lake-like environment. Hybrid offspring between different populations showed intermediate survival consistent with extrinsic postzygotic reproductive barriers. Our results suggest that both prezygotic (immigrant inviability) and postzygotic reproductive barriers contribute to ergence, and highlight the value of assessing multiple reproductive barriers acting at different stages and in natural contexts to understand speciation mechanisms.
Publisher: Wiley
Date: 27-06-2018
DOI: 10.1002/ECE3.4241
Publisher: American Association for the Advancement of Science (AAAS)
Date: 04-11-2016
Publisher: Oxford University Press (OUP)
Date: 12-01-2019
DOI: 10.1093/GBE/EVZ003
Location: France
No related grants have been discovered for Jelena Rajkov.