Hypervariable minisatellite regions are sites for crossing-over at meiosis in man.
In situ hybridization to human meiotic metaphase I (MI) preparations, using the labeled minisatellite core sequence lambda 33.15, showed clustering of autoradiographic grains principally at or around chiasmata, autosomal sites where crossing-over had occurred. For the XY bivalent, the pairing region formed between the terminal regions of the two short arms (Xpter Ypter), was also a principal site of labeling; in addition, the terminal region of the X long arm (Xqter) was labeled. Control experiments using a member of the human Alu family of dispersed repeated DNA sequences showed a much more randomized grain distribution, with clustering over chiasmata being far less obvious. The data provide support for the suggestion that polymorphic minisatellite regions within the human genome might play a significant role in pairing and/or recombination.
Chandley
A C
AC
MRC Human Gentics Unit, Western General Hospital, Edinburgh.
Mitchell
A R
AR
D002478:Cells, Cultured; D003434:Crossing Over, Genetic; D015342:DNA Probes; D004276:DNA, Satellite / Q000502:physiology*; D006801:Humans; D008540:Meiosis; D009693:Nucleic Acid Hybridization; D011995:Recombination, Genetic; D012091:Repetitive Sequences, Nucleic Acid
D015342:DNA Probes; D004276:DNA, Satellite