Heterosynapsis in a heterozygous fertile boar carrier of a 3;7 translocation.
Silver-stained synaptonemal complexes (SCs) in surface-spread pachytene nuclei from a boar, heterozygous for a reciprocal translocation, were analysed by electron microscopy. In such heterozygotes, cross-shaped quadrivalent configurations are expected to form in order to maximize homologous pairing. Contrary to the classical, expected cross-shaped configuration, heterosynapsis was often observed, with asymmetrical association in the lateral elements of the non-homologous partners of the quadrivalents. This heterosynapsis is assumed to be a mechanism preventing spermatocyte loss, but inducing a secondary segregational type of impairment of fertility due to foetal wastage leading to reduced prolificacy.
Gabriel-Robez
O
O
Institut d'Embryologie, Faculté de Médecine, Strasbourg, France.
Jaafar
H
H
Ratomponirina
C
C
Boscher
J
J
Bonneau
J
J
Popescu
C P
CP
Rumpler
Y
Y
D000818:Animals; D002871:Chromosome Banding; D006579:Heterozygote; D007621:Karyotyping; D008540:Meiosis; D008854:Microscopy, Electron; D008938:Mitosis; D012661:Semen / Q000032:analysis; D013552:Swine / Q000235:genetics*; D013573:Synaptonemal Complex; D014178:Translocation, Genetic