Genomic organization, sequence and polymorphism of the human chromosome 4-specific alpha-satellite DNA.

Two alpha-satellite fragments specific for human chromosome 4 have been cloned and characterized. Under stringent annealing conditions, they hybridized in situ only to the pericentromeric region of chromosome 4, but under non-stringent conditions they hybridized to all chromosomes containing the sequences of alpha-satellite suprachromosomal family 2 (viz., chromosomes 2, 4, 8, 9, 13, 14, 15, 18, 20, 21 and 22).

Chromosome-specific alpha satellites: two distinct families on human chromosome 18.

Two types of human chromosome 18-specific alpha satellite fragments have been cloned and sequenced. They represent closely related but distinct alphoid families formed by two different types of the higher-order repeated units (1360-bp EcoRI and 1700-bp HindIII fragments) that do not alternate in the genome. The individual repeats within each family are 99% identical and interfamily homology is about 78%.

[Specificity of the location of human chromosomes in the nucleus of a moving cell].

Data are presented on the distribution of centromeric heterochromatin of the human X-chromosome in the interphase nucleus of a moving cell. The in situ hybridization made it possible to obtain some results leading to the following conclusions: in moving fibroblasts centromeric heterochromatin of the X-chromosome is located in end regions of the interphase nucleus; there was no preferential localization noted of the centromeric region of the X-chromosome in the front or back areas of the nucleus as to the direction of the movement.

[Correlation of polymorphism of heterochromatin segments with hybridization on chromosome preparations of various cloned repeated human DNA sequences].

Comparison between results of measurements of heterochromatic regions detected by differential C and DA/DAP1 staining and the hybridization data of two cloned repeated human DNA sequences one alphoid (pH S05) and the other the satellite DNA III (pPD18) on chromosome preparations was made. A positive correlation of heterochromatic region sizes on several chromosomes and the amount of label over them detected after hybridization with both alphoid and satellite sequences was shown, the correlation with the latter being more pronounced.