Abstracts (first author)

Talk 

A novel genomic signature of adaptation from standing variation revealed in threespine stickleback

Author(s): Roesti M, Gavrilets S, Hendry AP, Salzburger W, Berner D

Summary:

Understanding how natural selection shapes the genome is becoming a major endeavor in evolutionary biology. Selection will often target pre-existing (standing) genetic variation. Nevertheless, theory has generally been developed for selection on novel variants. We here use extensive modeling tailored to adaptive divergence in threespine stickleback to characterize the genomic footprints of adaption from shared standing variation. The emerging predictions are then examined using genome-wide markers and targeted sequencing across many natural populations. Combined, our findings offer a novel explanation for heterogeneous genomic differentiation between diverging populations, challenge the widely held view that genomic regions of high and low population differentiation reliably point to loci under divergent and balancing selection, and allow us to propose a novel methodological framework for searching adaptation genes in natural populations.



Abstracts (coauthor)

Divergence between lake and stream populations in an East African cichlid fish

Author(s): Egger, B, Theis A, Ronco F, Indermaur A, Roesti M, Berner D, Salzburger W

Summary:

Integrative studies of species that occur along an environmental gradient provide important insights into ecological speciation and serve as prime examples for the presence of a speciation continuum. The cichlid species Astatotilapia burtoni occurs in lacustrine environment as well as in the surrounding rivers of Lake Tanganyika (LT), offering the possibility to study a lake-stream environmental gradient in a member of a large cichlid adaptive radiation in East Africa. We have established phylogeographic relationships and assessed the population structure in A. burtoni from the southern LT drainage using neutral nuclear (microsatellite) and mtDNA markers. We detect an unexpectedly high genetic diversity in A. burtoni, exceeding – at least in mtDNA – the diversity of the entire cichlid species flock of Lake Victoria, and a relatively complex phylogeographic pattern. Next, we have examined morphological differences among these populations by analyzing body shape. Based on these results, we focused on four lake-stream systems in detail. We here find that stream fish show a more inferior mouth, a more streamlined body, and shorter gill-rakers compared to lake fish, shifts presumably associated with differential foraging styles. Current work is now evaluating this hypothesis directly, and includes high-density SNP marker data generated by RADseq for population genomic analyses.

Contacts

Chairman: Octávio S. Paulo
Tel: 00 351 217500614 direct
Tel: 00 351 217500000 ext22359
Fax: 00 351 217500028
email: mail@eseb2013.com

Address

XIV Congress of the European Society for Evolutionary Biology

Organization Team
Department of Animal Biology (DBA)
Faculty of Sciences of the University of Lisbon
P-1749-016 Lisbon
Portugal

Website

Computational Biology & Population Genomics Group 
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