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Gene conversion between unlinked sequences in the germline of mice
J R Murti1, M Bumbulis, J C Schimenti
1Jackson Laboratory, Bar Harbor, Maine 04609.
Genetics
|July 1, 1994
Summary
Ectopic gene conversion, where genes on different chromosomes exchange DNA, is common in mice. This study developed a transgenic mouse model to show this process occurs frequently in the male germline, suggesting genes can evolve together even when separated.
Area of Science:
- Genetics
- Molecular Biology
- Evolutionary Biology
Background:
- Ectopic gene conversion is frequent in fungi, potentially due to genome-wide homology scanning.
- This process allows for the concerted evolution of dispersed homologous genes.
- Mammalian systems previously lacked tools to investigate ectopic gene conversion.
Purpose of the Study:
- To develop and utilize a binary transgenic mouse system to detect ectopic gene conversion in mice.
- To investigate the frequency and genomic location effects on ectopic gene conversion in the male germline.
Main Methods:
- A binary transgenic mouse system was established to visualize conversion events.
- Histochemical staining of spermatids and PCR amplification of transgenes in spermatozoa were used for detection.
- Analysis of hemizygous lacZ transgenes in different mouse lines.
Main Results:
- Ectopic gene conversion between unlinked, hemizygous lacZ transgenes was found to be frequent in the male germline (0.1–0.7% of spermatids).
- Conversion frequency varied between different transgenic lines, suggesting genomic location influences recombination susceptibility.
- The study demonstrates a functional system for studying ectopic gene conversion in mammals.
Conclusions:
- Homologous genes can undergo concerted evolution despite being genomically dispersed in mammals.
- Mechanisms may exist to modulate ectopic gene conversion, allowing for the divergence of duplicated genes.
- This research provides a novel tool for studying gene evolution and genome stability in mammals.