BRANTA — Jente Ottenburghs
Crossing Species Boundaries: The Hybrid Histories of the True Geese
Institution: Wageningen University, the Netherlands
Supervisors: Herbert H.T. Prins & Ronald C. Ydenberg
Details: PhD, 2016
Email
Subject Keywords:Hybridization, Introgression, Speciation, Genomics, Evolution, Phylogenetics
Species Keywords: Anser, Branta, Geese, Anseriformes, Anatidae
Abstract
Hybridization, the interbreeding of different species, is a common phenomenon in birds: about 16% of bird species is known to have hybridized with at least one other species. Numerous avian hybrid zones have been studied from a morphological or genetic perspective, often documenting the interspecific exchange of genetic material by hybridization and backcrossing (i.e. introgression). The incidence of hybridization amount bird orders with the Anseriformes (waterfowl: ducks, geese and swans) showing the highest propensity to hybridize. In this thesis, I provide a genomic perspective on the role of hybridization in the evolutionary history of one particular anseriform tribe, the Anserini or “True Geese”, which comprises 17 species divided over two genera: Anser and Branta . The diversification of this bird group took place in the late Pliocene and the early Pleistocene (between four and two million years ago), conceivably driven by a global cooling trend that led to the establishment of a circumpolar tundra belt and the emergence of temperate grasslands. Most species show a steady population increase during this period, followed by population subdivision during the Last Glacial Maximum about 110,000 to 12,000 years ago. The combination of large effective population sizes and occasional range shifts facilitated contact between the diverging goose species, resulting in high levels of interspecific gene flow. Introgressive hybridization might have enabled these goose populations to quickly adapt to changing environments by transferring of advantageous alleles across species boundaries, increasing standing genetic variation or expanding phenotypic variation of certain traits (e.g., beak morphology). Hybridization seems to be a common and integral component in the evolution and diversification of geese. The pervasiveness of rapid speciation and hybridization in geese complicates the attempt to capture their evolutionary history in a phylogenetic tree, therefore I advocate a phylogenetic network approach. Indeed, trying to capture the complex diversification of the True Geese in a branching tree can be regarded as a wild goose chase.
Published Papers
Ottenburghs, J., Megens, H.-J., Kraus, R.H.S., van Hooft, P., van Wieren, S.E., Crooijmans, R.P.M.A., Ydenberg, R.C., Groenen, M.A.M. & Prins, H.H.T. 2017. A History of Hybrids? Genomic Patterns of Introgression in the True Geese. BMC Evolutionary Biology. 17:201 https://doi.org/10.1186/s12862-017-1048-2
Ottenburghs, J., van Hooft, P., van Wieren, S.E., Ydenberg, R.C. & Prins, H.H.T. 2016. Birds in a Bush: Towards an Avian Phylogenetic Network. The Auk. 133:577-582 doi: https://dx.doi.org/10.1642/AUK-16-53.1
Ottenburghs, J., Megens, H.-J., Kraus, R.H.S., Madsen, O., van Hooft, P., van Wieren, S.E., Crooijmans, R.P.M.A., Ydenberg, R.C., Groenen, M.A.M. & Prins, H.H.T. 2016. A Tree of Geese: A Phylogenomic Perspective on the Evolutionary History of True Geese. Molecular Phylogenetics and Evolution. 101:303-313 doi:10.1016/j.ympev.2016.05.021
Ottenburghs, J., van Hooft, P., van Wieren, S.E., Ydenberg, R.C. & Prins, H.H.T. 2016. Hybridization in Geese: A Review. Frontiers in Zoology. 13:20 doiI: 10.1186/s12983-016-0153-1
Ottenburghs, J., Ydenberg, R.C., van Hooft, P., Van Wieren, S.E., & Prins, H.H.T. 2015. The Avian Hybrids Project: gathering the scientific literature on avian hybridization. Ibis, 157: 892-894 doi: 10.1111/ibi.12285