Physical localization of the 18S-5.8S-26S rDNA and sequence analysis of ITS regions in Thinopyrum ponticum (Poaceae: Triticeae): implications for concerted evolution.

ABSTRACT: Fluorescence in situ hybridization was used in Thinopyrum ponticum, a decaploid species, and its related diploid species, to investigate the distribution of the 18S-5.8S-26S rDNA. The distribution of rDNA was similar in all three diploid species (Th. bessarabicum, Th. elongatum and Pseudoroegneria stipifolia). Two pairs of loci were observed in each somatic cell at metaphase and interphase. One pair was located near the terminal end and the other in the interstitial regions of the short arms of one pair of chromosomes. However, all of the major loci in Th. ponticum were located on the terminal end of the short arms of chromosomes, and one chromosome had only one major locus. The maximum number of major loci detected on metaphase spreads was 20, which was the sum of that of its progenitors.

SUBMITTER: Li D 

PROVIDER: S-EPMC4240379 | biostudies-literature | 2002 Oct

REPOSITORIES: biostudies-literature