title: Analyses of diplotene chiasma frequencies in mouse oocytes and spermatocytes in relation to ageing and sexual dimorphism.
abstract: Diplotene chiasma frequencies from "early" (day 16) fetal oocytes are significantly greater than the average from "late" (day 18) oocytes. A decrease in chiasma frequencies from both ages was found at diakinesis/MI in oocytes of young or old adults females, indicating a loss of chiasmata and/or terminalization. A greater number of type I univalents was found in "late" oocytes than "early" oocytes entering diplotene. No difference were found in chiasma frequencies of male diplotene spermatocytes studied at 23 days, 2 months, or 24 months of age. A greater chiasma frequency was generally found in the female than the male at all ages studied.
mesh_terms: D000367:Age Factors; D000818:Animals; D002875:Chromosomes / Q000648:ultrastructure*; D003434:Crossing Over, Genetic; D005260:Female; D005865:Gestational Age; D008297:Male; D008540:Meiosis; D051379:Mice; D009865:Oocytes / Q000648:ultrastructure*; D010063:Ovum / Q000648:ultrastructure*; D012737:Sex Factors; D013090:Spermatocytes / Q000648:ultrastructure*; D013094:Spermatozoa / Q000648:ultrastructure*