Bidirectional interlocus concerted evolution following allopolyploid speciation in cotton (Gossypium)

摘要: Abstract Polyploidy is a prominent process in plant evolution; yet few data address the question of whether homeologous sequences evolve independently subsequent to polyploidization. We report on ribosomal DNA (rDNA) evolution five allopolyploid (AD genome) species cotton (Gossypium) and representing their diploid progenitors (A genome, D genome). Sequence from internal transcribed spacer regions (ITS1 ITS2) 5.8S gene indicate that rDNA arrays are homogeneous, or nearly so, all diploids allopolyploids examined. Because these occur at four chromosomal loci cotton, two each subgenome, repeats different must have become homogenized by interlocus concerted evolution. Southern hybridization analysis combined with copy-number estimation demonstrate this has gone completion near-completion it most likely involves entire repeat. Phylogenetic demonstrates been bidirectional species--i.e., polyploid lineages genome repeat type, whereas Gossypium mustelinum an A type. Although little known regarding functional significance sequences, study occurs for tandemly repeated plants. That can bidirectionally hybidization polyploidization significant implications phylogeny reconstruction, especially when based sequences.