| 1. |
- Enbody, Erik D., et al.
(author)
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A multispecies BCO2 beak color polymorphism in the Darwin's finch radiation
- 2021
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In: Current Biology. - : Elsevier. - 0960-9822 .- 1879-0445. ; 31:24, s. 5597-5604.e7
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Journal article (peer-reviewed)abstract
- Carotenoid-based polymorphisms are widespread in populations of birds, fish, and reptiles,(1) but generally little is known about the factors affecting their maintenance in populations.(2) We report a combined field and molecular-genetic investigation of a nestling beak color polymorphism in Darwin's finches. Beaks are pink or yellow, and yellow is recessive.(3) Here we show that the polymorphism arose in the Galapagos half a million years ago through a mutation associated with regulatory change in the BCO2 gene and is shared by 14 descendant species. The polymorphism is probably a balanced polymorphism, maintained by ecolog- ical selection associated with survival and diet. In cactus finches, the frequency of the yellow genotype is correlated with cactus fruit abundance and greater hatching success and may be altered by introgressive hybridization. Polymorphisms that are hidden as adults, as here, may be far more common than is currently recognized, and contribute to diversification in ways that are yet to be discovered.
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| 2. |
- Enbody, Erik D., et al.
(author)
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Community-wide genome sequencing reveals 30 years of Darwin's finch evolution
- 2023
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In: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 381:6665, s. 1427-
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Journal article (peer-reviewed)abstract
- A fundamental goal in evolutionary biology is to understand the genetic architecture of adaptive traits. Using whole-genome data of 3955 of Darwin's finches on the Galapagos Island of Daphne Major, we identified six loci of large effect that explain 45% of the variation in the highly heritable beak size of Geospiza fortis, a key ecological trait. The major locus is a supergene comprising four genes. Abrupt changes in allele frequencies at the loci accompanied a strong change in beak size caused by natural selection during a drought. A gradual change in Geospiza scandens occurred across 30 years as a result of introgressive hybridization with G. fortis. This study shows how a few loci with large effect on a fitness-related trait contribute to the genetic potential for rapid adaptive radiation.
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| 3. |
- Hill, Jason, et al.
(author)
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Spatiotemporal variations in retrovirus-host interactions among Darwin’s finches
- 2022
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In: Nature Communications. - : Springer Nature. - 2041-1723. ; 13:1
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Journal article (peer-reviewed)abstract
- Endogenous retroviruses (ERVs) are inherited remnants of retroviruses that colonized host germline over millions of years, providing a sampling of retroviral diversity across time. Here, we utilize the strength of Darwin’s finches, a system synonymous with evolutionary studies, for investigating ERV history, revealing recent retrovirus-host interactions in natural populations. By mapping ERV variation across all species of Darwin’s finches and comparing with outgroup species, we highlight geographical and historical patterns of retrovirus-host occurrence, utilizing the system for evaluating the extent and timing of retroviral activity in hosts undergoing adaptive radiation and colonization of new environments. We find shared ERVs among all samples indicating retrovirus-host associations pre-dating host speciation, as well as considerable ERV variation across populations of the entire Darwin’s finches’ radiation. Unexpected ERV variation in finch species on different islands suggests historical changes in gene flow and selection. Non-random distribution of ERVs along and between chromosomes, and across finch species, suggests association between ERV accumulation and the rapid speciation of Darwin’s finches.
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| 4. |
- Lamichhaney, Sangeet, 1984-, et al.
(author)
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Female-biased gene flow between two species of Darwin’s finches
- 2020
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In: Nature Ecology & Evolution. - : Springer Science and Business Media LLC. - 2397-334X. ; 4:7, s. 979-986
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Journal article (peer-reviewed)abstract
- The mosaic nature of hybrid genomes is well recognized, but little is known of how they are shaped initially by patterns of breeding, selection, recombination and differential incompatibilities. On the small Galápagos island of Daphne Major two species of Darwin’s finches, Geospiza fortis and G. scandens, hybridize rarely and backcross bidirectionally with little or no loss of fitness under conditions of plentiful food. We used whole genome sequences to compare genomes from periods before and after successful interbreeding followed by backcrossing. We inferred extensive introgression from G. fortis to G. scandens on autosomes and mitochondria but not on the Z chromosome. The unique combination of long-term field observations and genomic data shows that the reduction of gene flow for Z-linked loci reflects female-biased gene flow, arising from hybrid male disadvantage in competition for territories and mates, rather than from genetic incompatibilities at Z-linked loci.
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| 5. |
- Rubin, Carl-Johan, et al.
(author)
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Rapid adaptive radiation of Darwin's finches depends on ancestral genetic modules
- 2022
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In: Science Advances. - : American Association for the Advancement of Science (AAAS). - 2375-2548. ; 8:27
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Journal article (peer-reviewed)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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