Open AccessDifferent Patterns in Molecular Evolution of the Triticeae
Author(s) -
Vershinin Alexander V.,
Alkhimova Alena G.,
HeslopHarrison John S.,
Potapova Tatyana A.,
Omelianchuk Nadya
Publication year - 2001
Publication title -
hereditas
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.819
H-Index - 50
eISSN - 1601-5223
pISSN - 0018-0661
DOI - 10.1111/j.1601-5223.2001.t01-1-00153.x
Subject(s) - triticeae , retrotransposon , biology , phylogenetic tree , genome , genetics , evolutionary biology , phylogenetics , centromere , tandem repeat , eukaryotic chromosome fine structure , repeated sequence , segmental duplication , genome evolution , molecular evolution , gene , chromosome , transposable element , gene family
A huge part of the genomes of most Triticeae species is formed by different families of repetitive DN A sequences. In this paper the phylogenetic distribution of two major classes of the repeats, retrotransposons and tandemly organized DNA sequences, are considered and compared with the evolution of gene‐rich regions and generally accepted Triticeae phylogenetic relationships. In Hordeum , LTR‐containing retrotransposons are dispersed along the chromosomes and are consistent with the existing picture of the phylogeny of Hordeum. Another retrotransposon class, LINEs, have evolved independently from LTR‐retrotransposons. Different retrotransposon classes appear to have competed for genome space during the evolution of Hordeum. Another class of repeats, tandemly organized DNA sequences, tends to cluster at the functionally important regions of chromosomes, centromeres and telomeres. The distribution of a number of tandem DNA families in Triticeae is not congruent with generally accepted phylogenetic relationships. While natural selection is the dominant factor determining the structure of genie regions we suggest that the contribution of random events is important in the evolution of repetitive DNA sequences. The interplay of stochastic processes, molecular drive, and selection determines the structure of chromosomal regions, notably at centromeres and telomeres, stabilizing and differentiating species‐specific karyotypes. Thus, the evolution of these regions may occur largely independently of the evolution of gene‐rich regions.