Regularities of in situ nick translation labeling pattern of cereal metaphase chromosomes

A method of nick translation in situ that makes it possible to detect regions hypersensitive to DNase I in metaphase chromosomes has been modified for plants. Such regions have a peculiar structural conformation typical of transcriptionally active chromatin. The distribution of transcriptionally active regions labeled with [3H]TTP along the length of individual chromosomes of rye and B genome of wheat was studied. The following regularities of this distribution were found: a weak labeling of heterochromatic regions; an increase in the intensity of labeling in regions located at the border of euchromatin and heterochromatin and in the nucleolar organizer regions. Each chromosome of the B and R genomes has its own labeling pattern, but some similarities in the labeling pattern in all chromosomes have been revealed. Such similarities are characteristic of homoeologous chromosomes.Key words: wheat, modified nick translation, rye.