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- Hillier, Ladeana W, et al.
(författare)
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Sequence and comparative analysis of the chicken genome provide unique perspectives on vertebrate evolution
- 2004
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Ingår i: Nature. - 0028-0836 .- 1476-4687. ; 432:7018, s. 695-716
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Tidskriftsartikel (refereegranskat)abstract
- We present here a draft genome sequence of the red jungle fowl, Gallus gallus. Because the chicken is a modern descendant of the dinosaurs and the first non-mammalian amniote to have its genome sequenced, the draft sequence of its genome--composed of approximately one billion base pairs of sequence and an estimated 20,000-23,000 genes--provides a new perspective on vertebrate genome evolution, while also improving the annotation of mammalian genomes. For example, the evolutionary distance between chicken and human provides high specificity in detecting functional elements, both non-coding and coding. Notably, many conserved non-coding sequences are far from genes and cannot be assigned to defined functional classes. In coding regions the evolutionary dynamics of protein domains and orthologous groups illustrate processes that distinguish the lineages leading to birds and mammals. The distinctive properties of avian microchromosomes, together with the inferred patterns of conserved synteny, provide additional insights into vertebrate chromosome architecture.
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| 2. |
- Haynes, S, et al.
(författare)
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Phylogeography of the common vole (Microtus arvalis) with particular emphasis on the colonization of the Orkney archipelago
- 2003
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Ingår i: Molecular Ecology. - 0962-1083. ; 12:4, s. 951-956
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Tidskriftsartikel (refereegranskat)abstract
- To investigate the human introduction of the common vole Microtus arvalis onto the Orkney islands, the complete cytochrome b gene was sequenced in 41 specimens from both Orkney (four localities) and elsewhere in their range (26 localities). Orkney voles belonged to the same phylogenetic lineage, 'Western', as individuals from France and Spain indicating southwestern Europe as the most likely source area for the islands. This result is of interest with respect to the movement and trading links of the Neolithic people who likely transported the voles. As well as the Western lineage, our phylogenetic trees revealed three other purely European lineages: the 'Italian' (single specimen from N. Italy), the 'Central' (Germany, Netherlands, Denmark) and the 'Eastern' (Hungary, Slovakia, Poland, Ukraine, Finland, European Russia). Individuals from European Russia, W. Siberia, Georgia, Ukraine and Armenia formed a fifth distinct lineage coinciding with the distribution of the 'obscurus' chromosomal form of M. arvalis . These phylogeographical data suggest that M. arvalis occupied multiple refugia during the last glaciation.
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| 3. |
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| 4. |
- Jaarola, Maarit, et al.
(författare)
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Molecular phylogeny of the speciose vole genus Microtus (Arvicolinae, Rodentia) inferred from mitochondrial DNA sequences
- 2004
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Ingår i: Molecular Phylogenetics and Evolution. - : Elsevier BV. - 1095-9513 .- 1055-7903. ; 33:3, s. 647-663
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Forskningsöversikt (refereegranskat)abstract
- Voles of the genus Microtus represent one of the most speciose mammalian genera in the Holarctic. We established a molecular phylogeny for Microtus to resolve contentious issues of systematic relationships and evolutionary history in this genus. A total of 81 specimens representing ten Microtus species endemic to Europe as well as eight Eurasian, six Asian and one Holarctic species were sequenced for the entire cytochrome b gene (1140 bp). A further 25 sequences were retrieved from GenBank, providing data on an additional 23, mainly Nearctic, Microtus species. Phylogenetic analysis of these 48 species generated four well-supported monophyletic lineages. The genus Chionomys, snow voles, formed a distinct and well-supported lineage separate from the genus Microtus. The subgenus Microtus formed the strongest supported lineage with two sublineage displaying a close relationship between the arvalis species group (common voles) and the socialis species group (social voles). Monophyly of the Palearctic pitymyid voles, subgenus Terricola, was supported, and this subgenus was also subdivided into two monophyletic species groups. Together, these groupings clarify long-standing taxonomic uncertainties in Microtus. In addition, the "Asian" and the Nearctic lineages reported previously were identified although the latter group was not supported. However, relationships among the main Microtus branches were not resolved. suggesting a rapid and potentially Simultaneous radiation of a widespread ancestor early in the history of the genus. This and subsequent radiations discernible in the cytochrome b phylogeny, show the considerable potential of Microtus for analysis of historical and ecological determinants of speciation in small mammals. It is evident that speciation is an ongoing process in the genus and that the molecular data provides a vital insight into current species limits as well as cladogenic events of the past. (C) 2004 Elsevier Inc. All rights reserved.
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