[Spiralization dynamics of the eu- and heterochromatin of heteromorphic homologs of the 1st pair of human chromosomes].

Peculiarities of mitotic spiralization of eu- and heterochromatic parts of heteromorphic homologous chromosomes No 1 are investigated. The homologues differ in size of their centromeric heterochromatin segments. In the spiralization range studied (the total lengths of chromosome pair equal to 8.2+25.6 mcm) the lengths of any euchromatic and heterochromatic part change approximately by 3 and 2 times, resp. It is shown that if the chromosome contraction level is not taken into consideration, neither absolute nor relative length of heterochromatic segment can be used for measuring the ratio of heterochromatin. Recommendations for quantitative determination of heterochromatin in chromosome No 1 are given.