Persistence of two Y chromosomes through meiotic prophase and metaphase I in an XYY man.
Studies of spermatogenesis in an XYY male, presenting at a subfertility clinic, confirm the tendency for the germ cells to lose the second Y chromosome but for some XYY cells to reach metaphase I (MI). Light microscope studies of MI revealed the presence of YY bivalents and EM studies of microspread, silver-stained pachytene stages showed 30% of the cells to have two Y chromosomes; 13 out of 16 of these showing a YY synaptonemal complex. Strikingly, the Y axes show only partial synapsis; in no case was synapsis of the long arm heterochromatic regions apparent.
Speed
R M
RM
MRC Human Genetics Unit, Western General Hospital, Edinburgh, UK.
Faed
M J
MJ
Batstone
P J
PJ
Baxby
K
K
Barnetson
W
W
D006801:Humans; D007248:Infertility, Male / Q000235:genetics; D008297:Male; D008540:Meiosis; D008677:Metaphase; D008854:Microscopy, Electron; D011418:Prophase; D013737:Testis / Q000648:ultrastructure; D014997:XYY Karyotype; D014998:Y Chromosome / Q000648:ultrastructure