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A reciprocal autosomal translocation which causes male sterility in the mouse also impairs oogenesis
Abstract:
A quantitative histological analysis of ovaries from 3- and 5-day-old female mice heterozygous for the male-sterile reciprocal autosomal translocation, T(11;19)42H, revealed a marked reduction (by 65%) in the number of oocytes as compared to controls. These findings call into question the widely held view that chromosomal anomalies causing spermatogenic failure have no effect on oogenesis. It is suggested that during meiosis in males and females there is a mechanism operating which tends to eliminate cells which had incomplete chromosome pairing at the pachytene stage.
Insights
Chromosomal anomalies causing male sterility may impact female oocyte counts. This study found a 65% reduction in oocytes in mice with a specific translocation, suggesting a meiotic elimination mechanism.
Area of Science:
- Reproductive Biology
- Genetics
- Developmental Biology
Background:
- The widely held view is that chromosomal anomalies causing male sterility do not affect oogenesis.
- Reciprocal autosomal translocations can lead to male sterility due to spermatogenic failure.
Purpose of the Study:
- To investigate the effect of a male-sterile reciprocal autosomal translocation on oocyte numbers in female mice.
- To explore the potential impact of meiotic errors on oogenesis.
Main Methods:
- Quantitative histological analysis of ovaries from female mice (3- and 5-day-old) heterozygous for the T(11;19)42H translocation.
- Comparison of oocyte counts between affected mice and control groups.
Main Results:
- A significant reduction (65%) in the number of oocytes was observed in female mice heterozygous for the T(11;19)42H translocation compared to controls.
- This finding challenges the assumption that male-sterile chromosomal anomalies are without consequence for oogenesis.
Conclusions:
- Chromosomal anomalies associated with male sterility can negatively impact oocyte development.
- A meiotic mechanism may exist to eliminate cells with incomplete chromosome pairing during pachytene stage in both sexes.