Unique nucleotide polymorphism of ankyrin gene cluster in Arabidopsis.
The ankyrin (ANK) gene cluster is a part of a multigene family encoding ANK transmembrane proteins in Arabidopsis thaliana, and plays an important role in protein-protein interactions and in signal pathways. In contrast to other regions of a genome, the ANK gene cluster exhibits an extremely high level of DNA polymorphism in an approximately 5-kb region, without apparent decay. Phylogenetic analysis detects two clear, deeply differentiated haplotypes (dimorphism). The divergence between haplotypes of accession Col-0 and Ler-0 (Hap-C and Hap-L) is estimated to be 10.7%, approximately equal to the 10.5% average divergence between A. thaliana and A. lyrata. Sequence comparisons for the ANK gene cluster homologues in Col-0 indicate that the members evolve independently, and that the similarity among paralogues is lower than between alleles. Very little intralocus recombination or gene conversion is detected in ANK regions. All these characteristics of the ANK gene cluster are consistent with a tandem gene duplication and birth-and-death process. The possible mechanisms for and implications of this elevated nucleotide variation are also discussed, including the suggestion of balancing selection.
Du
Jianchang
J
State Key Laboratory of Pharmaceutical Biotechnology, Department of Biology, Nanjing University, Nanjing 210093, China. changzi75@hotmail.com
Wang
Xingna
X
Zhang
Mingsheng
M
Tian
Dacheng
D
Yang
Yong-Hua
YH
D017487:Ankyrins / Q000235:genetics*; D017360:Arabidopsis / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics; D001483:Base Sequence; D020440:Gene Duplication; D014644:Genetic Variation; D005843:Geography; D008969:Molecular Sequence Data; D005810:Multigene Family; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D020641:Polymorphism, Single Nucleotide
D017487:Ankyrins; D029681:Arabidopsis Proteins