| 1. |
- Almén, Markus Sällman, et al.
(författare)
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Adaptive radiation of Darwin's finches revisited using whole genome sequencing
- 2016
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Ingår i: Bioessays. - : Wiley. - 0265-9247 .- 1521-1878. ; 38:1, s. 14-20
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Tidskriftsartikel (refereegranskat)abstract
- We recently used genome sequencing to study the evolutionary history of the Darwin's finches. A prominent feature of our data was that different polymorphic sites in the genome tended to indicate different genetic relationships among these closely related species. Such patterns are expected in recently diverged genomes as a result of incomplete lineage sorting. However, we uncovered conclusive evidence that these patterns have also been influenced by interspecies hybridisation, a process that has likely played an important role in the radiation of Darwin's finches. A major discovery was that segregation of two haplotypes at the ALX1 locus underlies variation in beak shape among the Darwin's finches, and that differences between the two haplotypes in a 240 kb region in blunt and pointed beaked birds involve both coding and regulatory changes. As we review herein, the evolution of such adaptive haplotypes comprising multiple causal changes appears to be an important mechanism contributing to the evolution of biodiversity.
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| 2. |
- Lamichhaney, Sangeet, 1984-, et al.
(författare)
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A beak size locus in Darwin’s finches facilitated character displacement during a drought
- 2016
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 352:6284, s. 470-474
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Tidskriftsartikel (refereegranskat)abstract
- Ecological character displacement is a process of morphological divergence that reducescompetition for limited resources. We used genomic analysis to investigate the geneticbasis of a documented character displacement event in Darwin’s finches on Daphne Majorin the Galápagos Islands: The medium ground finch diverged from its competitor, the largeground finch, during a severe drought. We discovered a genomic region containing theHMGA2gene that varies systematically among Darwin’s finch species with different beaksizes. Two haplotypes that diverged early in the radiation were involved in the characterdisplacement event: Genotypes associated with large beak size were at a strong selectivedisadvantage in medium ground finches (selection coefficients= 0.59). Thus, a majorlocus has apparently facilitated a rapid ecological diversification in the adaptive radiationof Darwin’s finches.
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| 3. |
- Lamichhaney, Sangeet, et al.
(författare)
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Evolution of Darwin's finches and their beaks revealed by genome sequencing
- 2015
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 518:7539
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Tidskriftsartikel (refereegranskat)abstract
- Darwin's finches, inhabiting the Galapagos archipelago and Cocos Island, constitute an iconic model for studies of speciation and adaptive evolution. Here we report the results of whole-genome re-sequencing of 120 individuals representing all of the Darwin's finch species and two close relatives' Phylogenetic analysis reveals important discrepancies with the phenotype-based taxonomy. We find extensive evidence for interspecific gene flow throughout the radiation. Hybridization has given rise to species of mixed ancestry. A 240 kilobase haplotype encompassing the ALX1 gene that encodes a transcription factor affecting craniofacial. development is strongly associated with beak shape diversity across Darwin's finch species as well as within the medium ground finch (Geospiza fortis) a species that has undergone rapid evolution of beak shape in response to environmental changes. The ALX1 haplotype has contributed to diversification of beak shapes among the Darwin's finches and thereby, to an expanded utilization of food resources.
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| 4. |
- Rubin, Carl-Johan, et al.
(författare)
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Rapid adaptive radiation of Darwin's finches depends on ancestral genetic modules
- 2022
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Ingår i: Science Advances. - : American Association for the Advancement of Science (AAAS). - 2375-2548. ; 8:27
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Tidskriftsartikel (refereegranskat)abstract
- Recent adaptive radiations are models for investigating mechanisms contributing to the evolution of biodiversity. An unresolved question is the relative importance of new mutations, ancestral variants, and introgressive hybridization for phenotypic evolution and speciation. Here, we address this issue using Darwin's finches and investigate the genomic architecture underlying their phenotypic diversity. Admixture mapping for beak and body size in the small, medium, and large ground finches revealed 28 loci showing strong genetic differentiation. These loci represent ancestral haplotype blocks with origins predating speciation events during the Darwin's finch radiation. Genes expressed in the developing beak are overrepresented in these genomic regions. Ancestral haplotypes constitute genetic modules for selection and act as key determinants of the unusual phenotypic diversity of Darwin's finches. Such ancestral haplotype blocks can be critical for how species adapt to environmental variability and change.
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