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- Elsik, Christine G., et al.
(författare)
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The Genome Sequence of Taurine Cattle : A Window to Ruminant Biology and Evolution
- 2009
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 324:5926, s. 522-528
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Tidskriftsartikel (refereegranskat)abstract
- To understand the biology and evolution of ruminants, the cattle genome was sequenced to about sevenfold coverage. The cattle genome contains a minimum of 22,000 genes, with a core set of 14,345 orthologs shared among seven mammalian species of which 1217 are absent or undetected in noneutherian (marsupial or monotreme) genomes. Cattle-specific evolutionary breakpoint regions in chromosomes have a higher density of segmental duplications, enrichment of repetitive elements, and species-specific variations in genes associated with lactation and immune responsiveness. Genes involved in metabolism are generally highly conserved, although five metabolic genes are deleted or extensively diverged from their human orthologs. The cattle genome sequence thus provides a resource for understanding mammalian evolution and accelerating livestock genetic improvement for milk and meat production.
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| 2. |
- Struwe, Lena, et al.
(författare)
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Andean Speciation and Vicariance in Neotropical Macrocarpaea (Gentianaceae-Helieae)
- 2009
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Ingår i: Annals Of The Missouri Botanical Garden. - : Missouri Botanical Garden Press. - 0026-6493. ; 96:3, s. 450-469
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Konferensbidrag (refereegranskat)abstract
- The pains Macrocarpaea (Griseb.) Gilg (Gentianaceae. Helieae) is among the largest woody genera of tropical gentians, with most of its species occurring in the wet mountainous forest., of the Andes. Phylogenetic and dispersal-vicariance analyses (DIVA) of 57 of the 105 currently recognized species in the genus. Using two data sets front nuclear DNA (ITS and 5S-NTS sequences) and morphology. show it single origin of the Andean species front all ancestral distribution that includes southeastern Brazil. Within the Andes. species divide into two major clades: (1) northern species front the cordilleras of northern Ecuador, Colombia. and Venezuela; and (2) southern species of the Andean Amotape-Huancabamba Zone in Ecuador and Peru as well as the Andes of central and southern Peru and Bolivia. The Amotape-Huancabamba zone is supported as the ancestral area for Macrocarpaea within the Andes. There are repeated speciation patterns within the Andes, and three Mesoamerican species derive front the northern clade, as is the single sampled species front the Guayana Shield. The position of the subclade of the three Caribbean Species is less certain. but it currently nests among Andean species. An Atlantic coastal Brazilian clade is placed its sister group to all other Macrocarpaea, providing further support for all ancestral refuge in southeastern Brazil for the Helieae. The biogeographic analysis showed that local speciation is more common than long-distance dispersal, and allopatric speciation is more common than sympatric speciation. Using detailed, georeferenced herbarium collection data. patterns in environmental characteristics between clades and sister species were analyzed with Spatial Evolutionary and Ecological Vicariance, Analysis (SEEVA), utilizing geographic information system (GIS) and statistical methods. Sister clades and taxa were evaluated for statistical significance in variables such as annual rainfall and temperature, elevation, temperature and rainfall seasonality, geological bedrock age, and soil type to evaluate ecological vicariance between sister group. The results indicate that there are no general patterns for each variable, but that there are significant divergences in ecological niches between both larger sister groups and sister species, and ecological niche conservation was also observed when subsequent nodes in the phylogeny were compared.
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