Peter Kovalik
Well-known member
S. Wang, S. Rohwer, D. E. Irwin. Genomic insights of a moving Setophaga warbler hybrid zone. 27th IOC, Vancouver 2018, Oral Presentation.
Abstract:
Hybrid zones, where diverging populations interbreed, are natural arena for understanding the evolution of reproductive isolation underlying speciation. The rapid speciation of Setophaga warblers is an interesting speciation puzzle. We can understand such rapid speciation in hybrid zones between young Setophaga sister pairs. One of the hybrid zones between S. townsendi and S. occidentalis in the Pacific Northwest was thought to be moving over time, based on the shift of plumage hybrid index at the same sites over time. We found more signatures of movements in this hybrid zone: 1) the plumage cline have shifted 10km over 20 years; 2) there is a latitudinal gradient of genomic heterozygosity reduction from the current hybrid zone location to the postulated historical hybrid zone location; 3) there was asymmetry of linkage disequilibrium cline. However, when we looked at the genome-wide cline, there was no sign of shift between sampling periods. This pattern might be due to the fusion of gene pools between species in such rapidly moving and extensively hybridizing taxa. Thus a genome-wide association study (GWAS) was conducted to detect genetic regions underlying plumage variations in the genome. We found that although the plumage-associated genetic regions demonstrated more differentiation between parental populations than the rest of the genome, such differentiation decays over time. This study sheds light on population genetic cause and consequences of a moving hybrid zone, which is emergently needed for understanding populations, species, and speciation in the rapidly changing world.
Abstract:
Hybrid zones, where diverging populations interbreed, are natural arena for understanding the evolution of reproductive isolation underlying speciation. The rapid speciation of Setophaga warblers is an interesting speciation puzzle. We can understand such rapid speciation in hybrid zones between young Setophaga sister pairs. One of the hybrid zones between S. townsendi and S. occidentalis in the Pacific Northwest was thought to be moving over time, based on the shift of plumage hybrid index at the same sites over time. We found more signatures of movements in this hybrid zone: 1) the plumage cline have shifted 10km over 20 years; 2) there is a latitudinal gradient of genomic heterozygosity reduction from the current hybrid zone location to the postulated historical hybrid zone location; 3) there was asymmetry of linkage disequilibrium cline. However, when we looked at the genome-wide cline, there was no sign of shift between sampling periods. This pattern might be due to the fusion of gene pools between species in such rapidly moving and extensively hybridizing taxa. Thus a genome-wide association study (GWAS) was conducted to detect genetic regions underlying plumage variations in the genome. We found that although the plumage-associated genetic regions demonstrated more differentiation between parental populations than the rest of the genome, such differentiation decays over time. This study sheds light on population genetic cause and consequences of a moving hybrid zone, which is emergently needed for understanding populations, species, and speciation in the rapidly changing world.
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