scholarly journals Mitotic gene conversion can be as important as meiotic conversion in driving genetic variability in plants and other species without early germline segregation

PLoS Biology ◽  
2021 ◽  
Vol 19 (3) ◽  
pp. e3001164
Author(s):  
Xianqing Jia ◽  
Qijun Zhang ◽  
Mengmeng Jiang ◽  
Ju Huang ◽  
Luyao Yu ◽  
...  
Keyword(s):  
Genetic Variability ◽  
Gene Conversion ◽  
Allelic Diversity ◽  
Mitotic Rate ◽  
Rice Plants ◽  
Cell Divisions ◽  
Meiotic Gene ◽  
Mitotic Gene Conversion ◽  
Meiotic Event

In contrast to common meiotic gene conversion, mitotic gene conversion, because it is so rare, is often ignored as a process influencing allelic diversity. We show that if there is a large enough number of premeiotic cell divisions, as seen in many organisms without early germline sequestration, such as plants, this is an unsafe position. From examination of 1.1 million rice plants, we determined that the rate of mitotic gene conversion events, per mitosis, is 2 orders of magnitude lower than the meiotic rate. However, owing to the large number of mitoses between zygote and gamete and because of long mitotic tract lengths, meiotic and mitotic gene conversion can be of approximately equivalent importance in terms of numbers of markers converted from zygote to gamete. This holds even if we assume a low number of premeiotic cell divisions (approximately 40) as witnessed inArabidopsis. A low mitotic rate associated with long tracts is also seen in yeast, suggesting generality of results. For species with many mitoses between each meiotic event, mitotic gene conversion should not be overlooked.

scholarly journals Mitotic and meiotic gene conversion of Ty elements and other insertions in Saccharomyces cerevisiae.

Genetics ◽  
1989 ◽  
Vol 122 (4) ◽  
pp. 759-772
Author(s):  
A Vincent ◽  
T D Petes
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Gene Conversion ◽  
Point Mutations ◽  
Crossing Over ◽  
Yeast Saccharomyces Cerevisiae ◽  
Ty Elements ◽  
Meiotic Gene ◽  
Mitotic Gene Conversion

Abstract We examined meiotic and mitotic gene conversion events involved in deletion of Ty elements and other insertions from the genome of the yeast Saccharomyces cerevisiae. We found that Ty elements and one other insertion were deleted by mitotic gene conversion less frequently than point mutations at the same loci. One non-Ty insertion similar in size to Ty, however, did not show this bias. Mitotic conversion events deleting insertions were more frequently associated with crossing over than those deleting point mutations. In meiosis, conversion events duplicating the element were more common than those that deleted the element for one of the loci (HIS4) examined.

scholarly journals Molecular and cellular evidence for biased mitotic gene conversion in hybrid scallop

2010 ◽  
Vol 10 (1) ◽  
pp. 6 ◽  
Author(s):  
Shi Wang ◽  
Lingling Zhang ◽  
Jingjie Hu ◽  
Zhenmin Bao ◽  
Zhanjiang Liu
Keyword(s):  
Gene Conversion ◽  
Mitotic Gene Conversion

The Escherichia coli recA gene increases UV-induced mitotic gene conversion in Saccharomyces cerevisiae

1994 ◽  
Vol 25 (5) ◽  
pp. 472-474 ◽  
Author(s):  
Viera Vlčková ◽  
Luba Černáková ◽  
Eva Farkašová ◽  
Jela Brozmanová
Keyword(s):  
Escherichia Coli ◽  
Saccharomyces Cerevisiae ◽  
Gene Conversion ◽  
Reca Gene ◽  
Mitotic Gene Conversion

scholarly journals Genetic and physical analyses of sister chromatid exchange in yeast meiosis

1991 ◽  
Vol 11 (12) ◽  
pp. 6328-6336
Author(s):  
H Sun ◽  
D Dawson ◽  
J W Szostak
Keyword(s):  
Genetic Analysis ◽  
Gene Conversion ◽  
Mutant Strain ◽  
Sister Chromatid ◽  
Sister Chromatid Exchange ◽  
Physical Analysis ◽  
Single Stranded Dna ◽  
Meiotic Gene ◽  
Dna Fragment ◽  
Yeast Meiosis

We have used nonessential circular minichromosomes to monitor sister chromatid exchange during yeast meiosis. Genetic analysis shows that a 64-kb circular minichromosome undergoes sister chromatid exchange during 40% of meioses. This frequency is not reduced by the presence of a homologous linear minichromosome. Furthermore, sister chromatid exchange can be stimulated by the presence of a 12-kb ARG4 DNA fragment, which contains initiation sites for meiotic gene conversion. Using physical analysis, we have directly identified a product of sister chromatid exchange: a head-to-tail dimer form of a circular minichromosome. This dimer form is absent in a rad50S mutant strain, which is deficient in processing of the ends of meiosis-specific double-stranded breaks into single-stranded DNA tails. Our studies suggest that meiotic sister chromatid exchange is stimulated by the same mechanism as meiotic homolog exchange.

A yeast acts in (Cis) to inhibit meiotic gene conversion of adjacent sequences

Cell ◽  
1988 ◽  
Vol 52 (6) ◽  
pp. 863-873 ◽  
Author(s):  
Eric J. Lambie ◽  
G. Shirleen Roeder
Keyword(s):  
Gene Conversion ◽  
Meiotic Gene ◽  
In Cis

Evidence for Independent Mismatch Repair Processing on Opposite Sides of a Double-Strand Break in Saccharomyces cerevisiae

Genetics ◽  
1998 ◽  
Vol 148 (1) ◽  
pp. 59-70
Author(s):  
Yi-shin Weng ◽  
Jac A Nickoloff
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Gene Conversion ◽  
Mismatch Repair ◽  
Strand Break ◽  
Double Strand Break ◽  
Stem Loop ◽  
Mitotic Gene Conversion ◽  
Low Levels ◽  
Mat Locus ◽  
Insertion Mutations

Abstract Double-strand break (DSB) induced gene conversion in Saccharomyces cerevisiae during meiosis and MAT switching is mediated primarily by mismatch repair of heteroduplex DNA (hDNA). We used nontandem ura3 duplications containing palindromic frameshift insertion mutations near an HO nuclease recognition site to test whether mismatch repair also mediates DSB-induced mitotic gene conversion at a non-MAT locus. Palindromic insertions included in hDNA are expected to produce a stem-loop mismatch, escape repair, and segregate to produce a sectored (Ura+/−) colony. If conversion occurs by gap repair, the insertion should be removed on both strands, and converted colonies will not be sectored. For both a 14-bp palindrome, and a 37-bp near-palindrome, ~75% of recombinant colonies were sectored, indicating that most DSB-induced mitotic gene conversion involves mismatch repair of hDNA. We also investigated mismatch repair of well-repaired markers flanking an unrepaired palindrome. As seen in previous studies, these additional markers increased loop repair (likely reflecting corepair). Among sectored products, few had additional segregating markers, indicating that the lack of repair at one marker is not associated with inefficient repair at nearby markers. Clear evidence was obtained for low levels of short tract mismatch repair. As seen with full gene conversions, donor alleles in sectored products were not altered. Markers on the same side of the DSB as the palindrome were involved in hDNA less often among sectored products than nonsectored products, but markers on the opposite side of the DSB showed similar hDNA involvement among both product classes. These results can be explained in terms of corepair, and they suggest that mismatch repair on opposite sides of a DSB involves distinct repair tracts.

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