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High-frequency germ line gene conversion in transgenic mice.
J R Murti1, M Bumbulis, J C Schimenti
1Department of Genetics, School of Medicine, Case Western Reserve University, Cleveland, Ohio 45106.
Molecular and Cellular Biology
|June 1, 1992
Summary
Gene conversion in mice occurs frequently in germ cells, impacting genetic diversity. This high frequency suggests mechanisms may exist to prevent homogenization of duplicated genes during evolution.
Area of Science:
- Genetics
- Evolutionary Biology
- Molecular Biology
Background:
- Gene conversion, a nonreciprocal DNA transfer, influences gene family evolution by creating diversity or homogeneity.
- Measuring germline gene conversion frequency is challenging in mammals, unlike in simpler organisms.
- Understanding gene conversion in mammals is crucial for evolutionary insights.
Purpose of the Study:
- To develop and implement a system for quantifying germline gene conversion in mice.
- To analyze the frequency and implications of gene conversion in mammalian gametes.
Main Methods:
- A transgenic mouse system was engineered to detect intrachromosomal gene conversion.
- Recombination events were analyzed in male gametes (spermatids).
- Functional beta-galactosidase expression, driven by the lacZ gene, served as a marker for gene conversion.
Main Results:
- A high incidence of gene conversion (approx. 2%) was observed in mouse spermatids.
- Both meiotic and mitotic conversion events contributed to the observed frequency.
- Gene conversion was confirmed as an active process generating nonparental gametic haplotypes in mice.
Conclusions:
- Germline gene conversion is a frequent and active recombinational process in mice.
- The high frequency of gene conversion may pose challenges for the evolutionary divergence of duplicated genes.
- Mechanisms likely exist to decouple gene pairs from continuous homogenization via gene conversion.