caa a22 4500 386393117 CHVBK 20180307112126.0 cr unu---uuuuu 161130e198904 xx s 000 0 eng 10.1017/S0016672300027944 doi S0016672300027944 pii (NATIONALLICENCE)cambridge-10.1017/S0016672300027944 The influence of the Robertsonian translocation Rb(X.2)2Ad on anaphase I non-disjunction in male laboratory mice [Elektronische Daten] A Robertsonian translocation in the mouse between the X chromosome and chromosome 2 is described. The male and female carriers of the Rb(X.2)2Ad were fertile. A homozygous/hemizygous line was maintained. The influence of the X-autosomal Robertsonian translocation on anaphase I non-disjunction in male mice was studied by chromosome counts in cells at metaphase II of meoisis and by assessment of aneuploid progeny. The results conclusively show that the inclusion of Rb2Ad in the male genome induces non-disjunction at the first meoitic division. In second metaphase cells the frequency of sex-chromosomal aneuploidy was 10·8%, and secondary spermatocytes containing two or no sex chromosome were equally frequent. The Rb2Ad males sired 3·9% sex-chromosome aneuploid progeny. The difference in aneuploidy frequencies in the germ cells and among the progeny suggests that the viability of XO and XXY individuals is reduced. The pairing configurations of chromosomes 2, Rb2Ad and Y were studied during meiotic prophase by light and electron microscopy. Trivalent pairing was seen in all well spread nuclei. Complete pairing of the acrocentric autosome 2 with the corresponding segment of the Rb2Ad chromosome was only seen in 3·2% of the cells analysed in the electron microscope. The pairing between the X and the Y chromosome in the Rb2Ad males corresponded to that in males with normal karyotype. Reasons for sex-chromosomal non-disjunction despite the normal pairing pattern between the sex chromosomes may be seen in the terminal chiasma location coupled with the asynchronous separation of the sex chromosomes and the autosomes. The Rb2Ad chromosome can be useful for studies of X inactivation, as a marker for parental derivation of the X chromosome and for mapping loci by in situ hybridization. Copyright © Cambridge University Press 1989 Adler I.-D Institut für Säugetiergenetik, Gesellschaft für Strahlen- und Umweltforschung, D-8042 Neuherberg Johannisson R. Institut für Pathologie, Medizinische Universität zu Lübeck, D-2400 Lübeck, Federal Republic of Germany Winking H. Institut für Biologie, Medizinische Universität zu Lübeck, D-2400 Lübeck, Federal Republic of Germany Genetical Research Cambridge University Press 53/2(1989-04), 77-86 0016-6723 53:2<77 1989 53 GRH https://doi.org/10.1017/S0016672300027944 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1017/S0016672300027944 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Adler I.-D Institut für Säugetiergenetik, Gesellschaft für Strahlen- und Umweltforschung, D-8042 Neuherberg NATIONALLICENCE 700 1- Johannisson R. Institut für Pathologie, Medizinische Universität zu Lübeck, D-2400 Lübeck, Federal Republic of Germany NATIONALLICENCE 700 1- Winking H. Institut für Biologie, Medizinische Universität zu Lübeck, D-2400 Lübeck, Federal Republic of Germany NATIONALLICENCE 773 0- Genetical Research Cambridge University Press 53/2(1989-04), 77-86 0016-6723 53:2<77 1989 53 GRH CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-cambridge