Radiation-induced meiotic autosomal non-disjunction in male mice The effects of low doses of fission neutrons and X-rays in meiosis I and II of a Robertsonian translocation heterozygote

Nijhoff, J.H.; Boer, P. de

doi:10.1016/0027-5107(80)90117-7

Cited by 8 publications

(2 citation statements)

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“…This observation is not easily explained since the two products of the first meiotic division in male mammals are expected to be both observed at metaphase 11. A significant excess of secondary spermatocytes without the metacentric marker has been reported also for Rb( 11.13)4Bnr heterozygous male mice [20]. Theoretically, different frequencies of spermatocytes with or without the Rb metacentric could be observed if these cells differed in the length of the time period from anaphase I to metaphase 11.…”

Section: Discussionmentioning

confidence: 77%

“…The risk that women carrying a Rb for chromosome 21 will produce gametic malsegregation and abnormal offspring is higher than that for Rb heterozygous men [ 181. Nijhoff and de Boer [19,20] tested the hypothesis that a meiotic system with a high spontaneous rates of malsegregation would be more prone to a changed cellular environment, for example, after exposure to X-rays or fission neutrons. Contrary to expectations, the frequency of aneuploid secondary spermatocytes of heterozygous Rb( ll.I3)4Bnr mice was not increased after irradiation.…”

Section: Introductionmentioning

confidence: 99%

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Susceptibility to vinblastine‐induced aneuploidy and preferential chromosome segregation during meiosis I in Robertsonian heterozygous mice

Pacchierotti

Tiveron

Mailhes

et al. 1995

Teratog Carcinog Mutagen

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Chromosome segregation at meiosis I was studied in oocytes and spermatocytes of four different Robertsonian (Rb) heterozygous mouse stocks by cytogenetic analysis of meiotic products. Two Rb heterozygotes spontaneously yielded high frequencies of unbalanced oocytes. In one case, Rb(2.18)Rma, the excess hyperploidy was mainly accounted for by nondisjunction of normal bivalents, suggesting a generalized impairment of meiotic segregation. In each stock, frequencies of hyperploid spermatocytes were either not significantly different or significantly lower than the corresponding frequencies in the oocytes. This confirmed the greater risk of segregational errors in female than in male carriers of the same Rb metacentric. The hypothesis that an error prone system of meiotic segregation, such as the trivalent configuration of single Rb heterozygous oocytes, could be hypersensitive to chemically induced malsegregation was tested by injecting Rb heterozygous females with low doses of vinblastine (VBL). An intraperitoneal injection of 0.06 or 0.09 mg/kg VBL before the first meiotic division significantly increased the spontaneous frequency of hyperploid oocytes, inducing segregational errors of both the trivalent and normal bivalents. The comparison of these data with VBL effects in B6C3F1 mice showed that single Rb heterozygous oocytes are more sensitive to VBL-induced meiotic aneuploidy than oocytes with a standard karyotype. Although segregation distortion has been repeatedly shown in the progeny of Rb heterozygous mice with a significant excess of all telocentric balanced offspring, it has never been demonstrated whether this is a primary event occurring during meiotic segregation or a consequence of selective postconceptional death. In this study, we showed that preferential segregation occurred during female meiosis in all the Rb stocks tested. When segregation distortion was analyzed separately in balanced and unbalanced oocytes, the latter did not show preferential segregation, suggesting that, when the two telocentrics segregated from each other, then the metacentric was randomly directed to the ovum or the polar body.

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Section: Discussionmentioning

confidence: 77%

Section: Introductionmentioning

confidence: 99%