Most men were ascertained for a disturbance in reproduction and further investigations were undertaken when a constitutional chromosomal rearrangement was revealed. The material investigated is given in Tables 1 and 2. interesting findings on human male spermatocytes using modifications of the surface spreading techniques by Moses (1977), Fletcher (1979) and Solari (1980) as detailed in Hulten et al (1986). This presentation will give a broad outline of the most. The surface spreading technique has allowed a more detailed account of the pairing of chromosomes at first meiotic prophase than has been possible by traditional investigations (review in Moses et al 1985) and gives complementary information to that obtained by the more time consuming serial sectioning (review in Rasmussen and Holm 1980). Altogether, our data disclose a sex-specific difference in telomere dynamics and synapsis initiation patterns in male and female bovine germ cells that may be related to the sex-specific differences in recombination rates observed in this and other mammalian species. Further, we observed that synapsis in the female initiated both terminally and interstitially in earliest zygotene stage oocytes, which contrasts with the predominantly terminal synapsis initiation in early zygotene spermatocytes of the bovine male. Thus, the bouquet stage in the bovine female lasts significantly longer than in the male. Clustering of telomeres persisted during zygotene and even into the pachytene stage in a subset of nuclei, while it was absent in diplotene/dictyotene stage nuclei. Tight telomere clustering (bouquet formation) coincided with synapsis initiation at the leptotene/zygotene transition. intranuclear distribution in oogonia and relocated to the nuclear periphery during the preleptotene stage. We have therefore studied telomere dynamics by FISH and synapsis formation by immunostaining of synaptonemal complex proteins (SCP3, SCP1) on ovarian sections from 15 bovine fetuses, which covered the entire female prophase I. The process of homolog pairing is well characterised in meiosis of male mammals, but much less information is available from female meiosis.
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