The Genetics of Waterfowl Hybridization
Greylag (Anser anser) x Canada Goose (Branta canadensis)
Jente Ottenburghs Wageningen University Hasselt University (Belgium) – Bachelor Biology
Antwerp University (Belgium) – Master Biology: Evolution and Behavioral Biology
KHLim (Belgium) – Lector Chemistry
Wageningen University (the Netherlands) – PhD
De Volkskrant (the Netherlands) – Science Journalist
Karolinska Institutet (Sweden) – Postdoc
Uppsala University (Sweden) – Postdoc
Barnacle Goose (Branta leucopsis) How common is hybridization in birds?
Suchetet (1896) Gray (1958) McCarthy (2006) No Hybridization 16% of bird species hybridize in the wild Natural Hybridization 22% when including captive hybrids Captive Hybridization
The Avian Hybrids Project http://avianhybrids.wordpress.com/
Ottenburghs et al. (2015) Ibis Anseriformes = Hybrid Heaven
Mute Swan (Cygnus olor) x Greylag Goose (Anser anser) Mallard (Anas platyrhynchos) x Northern Pintail (A. acuta) “Swoose”
Wood Duck (Aix sponsa) x Chestnut Teal (Anas castanea) Anseriformes = Hybrid Heaven
Ottenburghs (2019) Avian Research Why do birds choose a partner from another species?
Barnacle Goose Greater White-fronted Goose
Lesser White-fronted Goose Ross’ Goose Hawaiian Goose Emperor Goose Ottenburghs et al. (2016) Frontiers in Zoology Argentine Ruddy Duck The consequences of hybridization: Introgression
https://biology.stackexchange.com/ Introgression is the exchange of genetic material
For example: humans and Neanderthals Adaptive Introgression: Exchanged DNA is beneficial
Anderson et al. (2009) Science Adaptive Introgression: Exchanged DNA is beneficial Darwin’s Finches American Buntings Genes involved in beak morphology Genes for adaptation to salty environment
Saltmarsh sparrow Nelson's sparrow
Lamichhaney et al. (2015) Nature Walsh et al. (2018) Evolution Hybrid Speciation: 1 + 1 = 3 House Sparrow x Spanish Sparrow = Italian Sparrow
Elgvin et al. (2017) Science Advances Hawaiian Duck
Mallard Laysan Duck Study System – The True Geese Livezey (1996) Donne-Gousse et al. (2002) Greater White-fronted Goose Gonzalez et al. (2009) (A. albifrons)
Lesser White-fronted Goose (A. erythropus)
Ruokonen et al. (2000) Lee et al. (2008)
Pink-footed Goose Taiga Bean Goose (A. brachyrhynchus) (A. fabalis) Phylogeny of geese not resolved Extensive Hybridization
What is the impact of hybridization on the evolutionary history of geese?
100bp PE 19 Goose Genomes 10-15X Coverage
Anser (“Grey Geese”) Anser (“White Geese”) Greater White-fronted Goose (A. albifrons) Snow Goose (A. caerulescens) Lesser White-fronted Goose (A. erythropus) Ross’ Goose (A. rossii) Pink-footed Goose (A. brachyrhynchus) Emperor Goose (A. canagicus) Tundra Bean Goose (A. serrirostris) Taiga Bean Goose (A. fabalis) Bar-headed Goose (A. indicus) Greylag Goose (A. anser) Swan Goose (A. cygnoides) Branta (“Black Geese”) Barnacle Goose (B. leucopsis) Canada Goose (B. canadensis) Cackling Goose (B. hutchinsii) Hawaii Goose (B. sandvicensis) Red-breasted Goose (B. ruficollis) Brent Goose (B. bernicla) [3 subspecies]
Estimating the Species Tree
Delsuc et al. 2005 Nature Reviews Genetics
Degnan & Rosenberg (2009) Trends in Ecology & Evolution Ottenburghs et al. (2016) Molecular Phylogenetics and Evolution
Finding Introgression D-statistic
ABBA BABA If D ≠ 0 and Z-score > 3 T=then there has been introgression
P1 P2 P3 O A B B A 18,937
B A B A 15,896
Outgroup
D = 0.087
Barnacle Cackling Canada Z-score = 4.32 Goose Goose Goose It’s not a tree but a network
Swan Goose Bar-headed Goose Greylag Goose
Taiga Bean Goose
Tundra Bean Goose Dark-bellied Brent Goose Pale-bellied Brent Goose Pink-footed Goose Black Brent Goose
Greater White-fronted Goose
Lesser White-fronted Goose
Red-breasted Goose
Snow Goose Ross’ Goose
Emperor Goose
Barnacle Goose
Cackling Goose Hawaiian Goose Canada Goose
Ottenburghs et al. (2017) BMC Evolutionary Biology Not only in birds... Hybridization Networks
Is the Red-breasted Goose a hybrid species?
Ottenburghs et al. (2017) BMC Evolutionary Biology Ottenburghs (2018) Ecology and Evolution What is a species?
The Biological Species Concept defines a species as members of populations that actually or potentially interbreed in nature What is a species? Mayden (1997): 24 species concepts • Agamospecies Concept (ASC) • Morphological Species Concept (MSC) • Biological Species Concept (BSC) • Non-dimensional Species Concept (NDSC) • Cladistic Species Concept (ClSC) • Phenetic Species Concept (PhSC) • Cohesion Species Concept (CSC) • Phylogenetic Species Concept (PSC) • Composite Species Concept (CpSC) • Diagnosable Version • Ecological Species Concept (EcSC) • Monophyly Version • Evolutionary Species Concept (ESC) • Diagnosable and Monophyly Version • Evolutionary Significant Unit (ESU) • Polythetic Species Concept (PtSC) • Genealogical Concordance Concept (GCC) • Recognition Species Concept (RSC) • Genetic Species Concept (GSC) • Reproductive Competition Concept (RCC) • Hennigian Species Concept (HSC) • Successional Species Concept (SSC) • Internodal Species Concept (ISC) • Taxonomic Species Concept (TSC) Speciation is a gradual process Species 1 Species 2 and different criteria arise at different times
Datasets Criteria Taxonomic grey zone
Morphological data Morphological species criteria
Social signals Species recognition criteria
Genomic data Phylogenetic species criteria
Ancestral population What is a species?
Taiga Bean Goose Tundra Bean Goose Subtle differences in beak morphology
Burgers et al. (1991) Ardea Different breeding sites and migration routes
Burgers et al. (1991) Ardea They can be separated genetically... Did Taiga and Tundra Bean Goose exchange DNA?
N0 N0
Ts Ts
NF NS NF NS
m mFS/mSF
N 0 N0 T s Ts
NF NS N N T F S m Tm
m /m FS SF mFS/mSF Taiga and Tundra Bean Goose separated about 2,5 million years ago, but they started hybridizing ca. 60,000 years ago.
N0
Ts
NF NS Tm
mFS/mSF Species 1 Species 2 Are they different species?
Criteria Taxonomic grey zone
Genetic differences
Morphological differences
Ecological differences
Taiga Bean Goose Tundra Bean Goose
Ancestral population