Structural variations of subterminal satellite blocks and their source mechanisms as inferred from the meiotic configurations of chimpanzee chromosome termini.

Structural variations of subterminal satellite blocks and their source mechanisms as inferred from the meiotic configurations of chimpanzee chromosome termini. Chromosome Res. 2019 Aug 15;: Authors: Hirai H, Hirai Y, Udono T, Matsubayashi K, Tosi AJ, Koga A Abstract African great apes have large constitutive heterochromatin (C-band) blocks in subtelomeric regions of the majority of their chromosomes, but humans lack these. Additionally, the chimpanzee meiotic cell division process demonstrates unique partial terminal associations in the first meiotic prophase (pachytene). These are likely formed as a result of interaction among subtelomeric C-band blocks. We thus conducted an extensive study to define the features in the subtelomeric heterochromatic regions of chimpanzee chromosomes undergoing mitotic metaphase and meiotic cell division. Molecular cytogenetic analyses with probes of both subterminal satellite DNA (a main component of C-band) and rDNA demonstrated principles of interaction among DNA arrays. The results suggest that homologous and ectopic recombination through persistent subtelomeric associations (post-bouquet association observed in 32% of spermatocytes in the pachytene stage) appears to create variability in heterochromatin patterns and simultaneously restrain subtelomeric genome polymorphisms. That is, the meeting of non-homologous chromosome termini sets the stage for ectopic pairing which, in turn, is the mechanis...
Source: Chromosome Research - Category: Genetics & Stem Cells Authors: Tags: Chromosome Res Source Type: research