Meiotic synapsis proceeds from a limited number of subtelomeric sites in the human male.
The formation of the synaptonemal complex (SC) is a crucial early step in the meiotic process, but relatively little is known about the establishment of the human SC. Accordingly, we recently initiated a study of synapsis in the human male, combining immunofluorescence and fluorescence in situ hybridization methodologies to analyze prophase spermatocytes from a series of control individuals. Our results indicate that synapsis is a tightly regulated process, with relatively little variation among individuals. On nonacrocentric chromosomes, there are two synaptic initiation sites, one on the distal short arm and one on the distal long arm, whereas acrocentric chromosomes exhibit a single site on the distal long arm. For both types of chromosomes, synapsis then proceeds toward the centromere, with little evidence that specific p- or q-arm sequences affect the process. However, the centromere appears to have an inhibitory effect on synapsis--that is, when one arm of a nonacrocentric chromosome is "zippered up" before the other, the centromere acts as a barrier to further movement from that arm.
Brown
Petrice W
PW
Center for Human Genetics, Case Western Reserve University School of Medicine and University Hospitals of Cleveland, Cleveland, OH, USA.
Judis
Luann
L
Chan
E Ricky
ER
Schwartz
Stuart
S
Seftel
Allen
A
Thomas
Anthony
A
Hassold
Terry J
TJ
D000328:Adult; D023902:Chromosome Pairing; D005455:Fluorescent Antibody Technique; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D008540:Meiosis / Q000235:genetics*; D011995:Recombination, Genetic; D016615:Telomere