کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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2835621 | 1164348 | 2007 | 16 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Evolutionary dynamics of Waxy and the origin of hexaploid Spartina species (Poaceae) Evolutionary dynamics of Waxy and the origin of hexaploid Spartina species (Poaceae)](/preview/png/2835621.png)
We investigated the evolutionary dynamics of duplicated copies of the granule-bound starch synthase I gene (GBSSI or Waxy) within polyploid Spartina species. Molecular cloning, sequencing, and phylogenetic analyses revealed incongruences between the expected species phylogeny and the inferred gene trees. Some genes within species were more divergent than expected from ploidy level alone, suggesting the existence of paralogous sets of Waxy loci in Spartina. Phylogenetic analyses indicate that this paralogy originated from a duplication that occurred prior to the divergence of Spartina from other Chloridoideae. Gene tree topologies revealed three divergent homoeologous sequences in the hexaploid S. alterniflora that are consistent with the proposal of an allopolyploid origin of the hexaploid clade. Waxy sequences differ in insertion–deletion events in introns, which may be used to diagnose gene copies. Both paralogous and homoeologous coding regions appear to evolving under selective constraints.
Journal: Molecular Phylogenetics and Evolution - Volume 43, Issue 3, June 2007, Pages 1040–1055