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Analysis of synaptonemal complexes in bulls and rams, carriers of XY/XX chimerism

REJDUCH B, SLOTA E, SYSA PS, KWACZYNSKA A
Veterinarni Medicina 45, 2000, 311-313

The aim of this study was to investigate synaptonemal complexes in the bulls and rams originated from heterozygotic twins. We diagnosed dissociation of sex bivalents in the early stage of pachytene. Tissue samples used in this study were obtained from testes after castration of bulls and rams, carriers of the XY/XX chimerism. The analysis of 106 spermatocytes from two chimeric bulls and 175 spermatocytes from three chimeric rams was performed under the light microscope. The results obtained for chimeric animals and animals characterized by the normal karyotype were then compared. We found that the level of early dissociation of X-Y bivalent in chimeric bulls ranged from 2.0% to 5.6% (in the normal bulls - 3.1%). Furthermore, in the chimeric rams, frequency of the early dissociation was higher and ranged from 11.1% to 19.0% (in the normal rams - 3.4%). The early dissociation of sex bivalent could possibly be the cause of the lower fertility in males originating from dizygotic twinning


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