| 1. |
- Dudaniec, Rachael, et al.
(författare)
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Genetic and morphological divergence in island and mainland birds: Informing conservation priorities
- 2011
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Ingår i: Biological Conservation. - : Elsevier BV. - 1873-2917 .- 0006-3207. ; 144:12, s. 2902-2912
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Tidskriftsartikel (refereegranskat)abstract
- Evolutionary processes can complicate conservation efforts for species with uncertain taxonomic classifications and discrete geographic populations. Discordant morphological and genetic patterns across the geographic range of species further calls for the identification of evolutionary significant units for conservation. Using island and mainland populations of a small Australian passerine (the superb fairy-wren, Malurus cyaneus), we examine the relationship between morphological and genetic divergence among two subspecies, M. c. ashbyi (Kangaroo Island, South Australia) and M. c. leggei (South Australia, mainland), using eight microsatellite markers. Island birds showed clear evidence for morphological divergence, with a larger body size and thinner bill compared to mainland birds. Two genetic clusters were found using Bayesian methods, comprising mainland and island regions. Estimates of recent migration rates between all sites were very low (<2%). Morphological and genetic differentiation between island and mainland sites correlated significantly, but not when controlling for isolation by distance. Genetic and morphological substructure was evident with three distinct genetic clusters in each region. Males, the highly sedentary sex, appeared to drive correlations between morphological and genetic differentiation. Our study provides evidence that the subspecies classification of M. cyaneus in island and mainland regions encapsulates two independently diverging populations that can be recognised in conservation planning.
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| 2. |
- Gemmell, Neil J., et al.
(författare)
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The tuatara genome reveals ancient features of amniote evolution
- 2020
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Ingår i: Nature. - : Springer Nature. - 0028-0836 .- 1476-4687. ; 584:7821, s. 403-409
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Tidskriftsartikel (refereegranskat)abstract
- The tuatara (Sphenodon punctatus)—the only living member of the reptilian order Rhynchocephalia (Sphenodontia), once widespread across Gondwana1,2—is an iconic species that is endemic to New Zealand2,3. A key link to the now-extinct stem reptiles (from which dinosaurs, modern reptiles, birds and mammals evolved), the tuatara provides key insights into the ancestral amniotes2,4. Here we analyse the genome of the tuatara, which—at approximately 5 Gb—is among the largest of the vertebrate genomes yet assembled. Our analyses of this genome, along with comparisons with other vertebrate genomes, reinforce the uniqueness of the tuatara. Phylogenetic analyses indicate that the tuatara lineage diverged from that of snakes and lizards around 250 million years ago. This lineage also shows moderate rates of molecular evolution, with instances of punctuated evolution. Our genome sequence analysis identifies expansions of proteins, non-protein-coding RNA families and repeat elements, the latter of which show an amalgam of reptilian and mammalian features. The sequencing of the tuatara genome provides a valuable resource for deep comparative analyses of tetrapods, as well as for tuatara biology and conservation. Our study also provides important insights into both the technical challenges and the cultural obligations that are associated with genome sequencing.
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