Breaking free from the tree – reconstructing the ancestral genomic history of species

Different parts of the genome have different genealogical histories. In this figure, horizontal lines represent the genomes of three species – human, chimpanzee and gorilla. The phylogenetic tree reconstructed from the purple segment groups humans and chimpanzees, who they share a closer common ancestor. The tree reconstructed from the green segment, in contrast, groups humans and gorillas together. Characterizing the phylogenetic history of these genomic fragments can help us understand how natural selection has affected the genomes of the ancestral species.

25 September 2023 by Lisbeth Heilesen

The ancestral history of the genomes of different species cannot be represented with a single phylogenetic tree. Instead, due to the effect of recombination, different parts of the genome have different evolutionary histories. Using statistical and computational tools to compare the mutations accumulated in the DNA of present-day species, Iker Rivas-González inferred these different evolutionary histories along the genomes of diverse animal groups, including primates, marsupials and birds. With this information, Iker Rivas-González characterized which genes were affected by natural selection in the ancestral species millions of years in the past, which include, for example, immune system genes. Apart from analyzing empirical data, Iker Rivas-González also contributed to developing new algorithms to reconstruct the ancestral history of species more accurately.
The PhD study was completed at Bioinformatics Research Centre (BiRC), Faculty of Natural Sciences, Aarhus University.

This summary was prepared by the PhD student.

Time: Monday, 25th September 2023 at 14:00
Place: Building 1870-716, Bioinformatics Research Centre (BiRC), Aarhus University, Universitetsbyen 81, 8000 Aarhus C
Title of PhD thesis: Ancestral multi-species population genomics

Contact information: Iker Rivas-González, e-mail: irg@birc.au.dk, tel.: +45 44 18 53 44

Members of the assessment committee:
Professor Richard Durbin, Department of Genetics, University of Cambridge, United Kingdom

Professor Matthew Hahn, Department of Biology and Department of Computer Science, Indiana University, United States of America

Associate Professor Thomas Bataillon (chair), Bioinformatics Research Centre (BiRC), Aarhus University, Denmark

Main supervisor:
Professor Mikkel Heide Schierup, Bioinformatics Research Centre (BiRC), Aarhus University, Denmark

Language: The PhD dissertation will be defended in English

The defence is public.
The PhD thesis is available for reading at the Graduate School of Natural Sciences/GSNS, Jens Baggesens Vej 53, building 5221, 8200 Aarhus N.