Genetic Conversion

2019 ◽  
Author(s):  
Jessica L. Roberts
Keyword(s):  
Genetic Conversion

scholarly journals Conversion of deletions during recombination in pneumococcal transformation.

Genetics ◽  
1989 ◽  
Vol 123 (3) ◽  
pp. 455-464
Author(s):  
J C Lefèvre ◽  
P Mostachfi ◽  
A M Gasc ◽  
E Guillot ◽  
F Pasta ◽  
...  
Keyword(s):  
Dna Repair ◽  
Genetic Analysis ◽  
Dna Polymerase ◽  
Point Mutations ◽  
Dna Molecules ◽  
Wild Type ◽  
Repair Synthesis ◽  
Dna Repair Synthesis ◽  
Genetic Conversion

Abstract Genetic analysis of 16 deletions obtained in the amiA locus of pneumococcus is described. When present on donor DNA, all deletions increased drastically the frequency of wild-type recombinants in two-point crosses. This effect was maximal for deletions longer than 200 bases. It was reduced for heterologies shorter than 76 bases and did not exist for very short deletions. In three-point crosses in which the deletion was localized between two point mutations, we demonstrated that this excess of wild-type recombinants was the result of a genetic conversion. This conversion extended over several scores of bases outside the deletion. Conversion takes place during the heteroduplex stage of recombination. Therefore, in pneumococcal transformation, long heterologies participated in this heteroduplex configuration. As this conversion did not require an active DNA polymerase A gene it is proposed that the mechanism of conversion is not a DNA repair synthesis but involves breakage and ligation between DNA molecules. Conversion of deletions did not require the Hex system of correction of mismatched bases. It differs also from localized conversion. It appears that it is a process that evolved to correct errors of replication which lead to long heterologies and which are not eliminated by other systems.

scholarly journals Genetic conversion of a split-drive into a full-drive element

2021 ◽  
Author(s):  
Gerard Terradas ◽  
Jared B. Bennett ◽  
Zhiqian Li ◽  
John M. Marshall ◽  
Ethan Bier
Keyword(s):  
Gene Drive ◽  
Fitness Costs ◽  
Experimental Proof ◽  
Guide Rna ◽  
Split Gene ◽  
Core Components ◽  
Beneficial Traits ◽  
Drive Systems ◽  
Genetic Conversion ◽  
Gene Drives

AbstractGene-drive systems offer an important new avenue for spreading beneficial traits into wild populations. Their core components, Cas9 and guide RNA (gRNA), can either be linked within a single cassette (full gene drive, fGD) or provided in two separate elements (split gene drive, sGD) wherein the gRNA-bearing element drives in the presence of an independent static source of Cas9. We previously designed a system engineered to turn split into full gene drives. Here, we provide experimental proof-of-principle for such a convertible system inserted at the spo11 locus, which is recoded to restore gene function. In multigenerational cage studies, the reconstituted spo11 fGD cassette initially drives with slower kinetics than the unlinked sGD element (using the same Mendelian vasa-Cas9 source), but eventually reaches a similar level of final introgression. Different kinetic behaviors may result from transient fitness costs associated with individuals co-inheriting Cas9 and gRNA transgenes during the drive process.

Interspecific genetic linkage map, segregation distortion and genetic conversion in coffee (Coffea sp.)

2000 ◽  
Vol 101 (4) ◽  
pp. 669-676 ◽  
Author(s):  
C. L. Ky ◽  
P. Barre ◽  
M. Lorieux ◽  
P. Trouslot ◽  
S. Akaffou ◽  
...  
Keyword(s):  
Linkage Map ◽  
Segregation Distortion ◽  
Genetic Linkage ◽  
Genetic Linkage Map ◽  
Genetic Conversion

scholarly journals The extent to which gene conversion can change allele frequencies in populations

1982 ◽  
Vol 39 (2) ◽  
pp. 199-217 ◽  
Author(s):  
B. C. Lamb ◽  
S. Helmi
Keyword(s):  
Gene Conversion ◽  
Allele Frequencies ◽  
Numerical Examples ◽  
Critical Comparison ◽  
Control Factors ◽  
Ascobolus Immersus ◽  
Genetic Conversion

SummaryThe gene conversion parameters which affect allele frequencies in populations are defined, and their ranges and typical values are given for several genera of fungi, where meiotic octads and tetrads provide the best information on conversion. Both gene conversion and disparity in direction of conversion are common. Data from Ascobolus immersus show that conversion properties are largely stable with time, but can be changed environmentally and by genetic conversion control factors. Equations are given for the interactions of selection, mutation and gene conversion in determining equilibrium frequencies. Numerical examples, using typical values of conversion parameters from the fungal data, show that for alleles which are selectively neutral or have very low selection coefficients, conversion will often have very large effects on their equilibrium frequencies and may lead to fixation. Where selection coefficients are higher, conversion has major effects on the frequencies of deleterious recessive alleles, but lesser effects on deleterious dominant alleles: a critical comparison is that of s with 2y. The available estimates for conversion parameters (at least in fungi) are of a magnitude to make gene conversion an important factor in evolution.

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