scholarly journals Role of cis, trans, and inbreeding effects on meiotic recombination in Saccharomyces cerevisiae

2018 ◽  
Author(s):  
Xavier Raffoux ◽  
Mickael Bourge ◽  
Fabrice Dumas ◽  
Olivier C. Martin ◽  
Matthieu Falque

ABSTRACTMeiotic recombination is a major driver of genome evolution by creating new genetic combinations. To probe the factors driving variability of meiotic recombination, we used a high-throughput method to measure recombination rates in 26 S. cerevisiae strains from different geographic origins and habitats. Fourteen intervals were monitored for each strain, covering chromosomes VI and XI entirely, and part of chromosome I. We found an average number of crossovers per chromosome ranging between 1.0 and 9.5 across strains (“domesticated” or not), which is higher than the average between 0.5 and 1.5 found in most organisms. In the different intervals analyzed, recombination showed up to 9-fold variation across strains but global recombination landscapes along chromosomes varied less. We also built an incomplete diallel experiment to measure recombination rates in one region of chromosome XI in 10 different crosses involving five parental strains. Our overall results indicate that recombination rate is increasingly positively correlated with sequence similarity between homologs (i) in DSB rich regions within intervals, (ii) in entire intervals, and (iii) at the whole genome scale. Therefore, these correlations cannot be explained by cis-effects only. In addition, by using a quantitative genetics analysis, we identified an inbreeding effect that reduces recombination rate in homozygous genotypes while other interaction effects (specific combining ability) or additive effects (general combining ability) are found to be weak. Finally, we measured significant crossover interference in some strains, and interference intensity was positively correlated with crossover number.Author SummaryMeiosis is a key process for sexually reproducing organisms by producing gametes with a halved set of genetic material. An essential step of meiosis is the formation of crossovers which are reciprocal exchanges of genetic material between chromosomes inherited from both parents. Crossovers ensure proper chromosome segregation and thus viable gametes. They also create novel genetic diversity which contributes to evolution and permits genetic improvement of agriculturally important species. Most living organisms produce between one and three crossovers per chromosome, and tight regulatory mechanisms control the number of crossovers and their distribution along chromosomes. In spite of their potential importance for biotechnological applications, such mechanisms are still poorly understood.Using a high throughput method based on fluorescent markers, we investigated the diversity of recombination in the budding yeast Saccharomyces cerevisiae. We observed up to 9-fold differences in numbers of crossovers across hybrids obtained by crossing different strains with a common tester, and this variation was correlated with the degree of DNA sequence similarity between homologous chromosomes. By also investigating homozygotes, we conclude that on the one hand too much sequence divergence impairs recombination in distantly-related hybrids, and on the other hand complete homozygosity is also associated with lower numbers of crossovers.

2020 ◽  
Vol 37 (12) ◽  
pp. 3654-3671
Author(s):  
Kevin H -C Wei ◽  
Aditya Mantha ◽  
Doris Bachtrog

Abstract Recombination is the exchange of genetic material between homologous chromosomes via physical crossovers. High-throughput sequencing approaches detect crossovers genome wide to produce recombination rate maps but are difficult to scale as they require large numbers of recombinants individually sequenced. We present a simple and scalable pooled-sequencing approach to experimentally infer near chromosome-wide recombination rates by taking advantage of non-Mendelian allele frequency generated from a fitness differential at a locus under selection. As more crossovers decouple the selected locus from distal loci, the distorted allele frequency attenuates distally toward Mendelian and can be used to estimate the genetic distance. Here, we use marker selection to generate distorted allele frequency and theoretically derive the mathematical relationships between allele frequency attenuation, genetic distance, and recombination rate in marker-selected pools. We implemented nonlinear curve-fitting methods that robustly estimate the allele frequency decay from batch sequencing of pooled individuals and derive chromosome-wide genetic distance and recombination rates. Empirically, we show that marker-selected pools closely recapitulate genetic distances inferred from scoring recombinants. Using this method, we generated novel recombination rate maps of three wild-derived strains of Drosophila melanogaster, which strongly correlate with previous measurements. Moreover, we show that this approach can be extended to estimate chromosome-wide crossover interference with reciprocal marker selection and discuss how it can be applied in the absence of visible markers. Altogether, we find that our method is a simple and cost-effective approach to generate chromosome-wide recombination rate maps requiring only one or two libraries.


Genetics ◽  
1988 ◽  
Vol 119 (1) ◽  
pp. 21-34
Author(s):  
C W Moore ◽  
D M Hampsey ◽  
J F Ernst ◽  
F Sherman

Abstract Recombination rates have been examined in two-point crosses of various defined cyc1 mutations that cause the loss or nonfunction of iso-1-cytochrome c in the yeast Saccharomyces cerevisiae. Recombinants arising by three different means were investigated, including X-ray induced mitotic recombination, spontaneous mitotic recombination, and meiotic recombination. Heteroallelic diploid strains were derived by crossing cyc1 mutants containing a series of alterations at or near the same site to cyc1 mutants containing alterations at various distances. Marked disproportionalities between physical distances and recombination frequencies were observed with certain cyc1 mutations, indicating that certain mismatched bases can significantly affect recombination. The marker effects were more pronounced when the two mutational sites of the heteroalleles were within about 20 base pairs, but separated by at least 4 base pairs. Two alleles, cyc1-163 and cyc1-166, which arose by G.C----C.G transversions at nucleotide positions 3 and 194, respectively, gave rise to especially high rates of recombination. Other mutations having different substitutions at the same nucleotide positions were not associated with abnormally high recombination frequencies. We suggest that these marker effects are due to the lack of repair of either G/G or C/C mismatched base pairs, while the other mismatched base pair of the heteroallele undergoes substantial repair. Furthermore, we suggest that diminished recombination frequencies are due to the concomitant repair of both mismatches within the same DNA tract.


2009 ◽  
Vol 24 (1) ◽  
pp. 103-107 ◽  
Author(s):  
John M. C. Danku ◽  
Luke Gumaelius ◽  
Ivan Baxter ◽  
David E. Salt

2017 ◽  
Author(s):  
Morgane Petit ◽  
Jean-Michel Astruc ◽  
Julien Sarry ◽  
Laurence Drouilhet ◽  
Stéphane Fabre ◽  
...  

AbstractRecombination is a complex biological process that results from a cascade of multiple events during meiosis. Understanding the genetic determinism of recombination can help to understand if and how these events are interacting. To tackle this question, we studied the patterns of recombination in sheep, using multiple approaches and datasets. We constructed male recombination maps in a dairy breed from the south of France (the Lacaune breed) at a fine scale by combining meiotic recombination rates from a large pedigree genotyped with a 50K SNP array and historical recombination rates from a sample of unrelated individuals genotyped with a 600K SNP array. This analysis revealed recombination patterns in sheep similar to other mammals but also genome regions that have likely been affected by directional and diversifying selection. We estimated the average recombination rate of Lacaune sheep at 1.5 cM/Mb, identified about 50,000 crossover hotspots on the genome and found a high correlation between historical and meiotic recombination rate estimates. A genome-wide association study revealed two major loci affecting inter-individual variation in recombination rate in Lacaune, including the RNF212 and HEI10 genes and possibly 2 other loci of smaller effects including the KCNJ15 and FSHR genes. Finally, we compared our results to those obtained previously in a distantly related population of domestic sheep, the Soay. This comparison revealed that Soay and Lacaune males have a very similar distribution of recombination along the genome and that the two datasets can be combined to create more precise male meiotic recombination maps in sheep. Despite their similar recombination maps, we show that Soay and Lacaune males exhibit different heritabilities and QTL effects for inter-individual variation in genome-wide recombination rates.


Yeast ◽  
2018 ◽  
Vol 35 (6) ◽  
pp. 431-442 ◽  
Author(s):  
Xavier Raffoux ◽  
Mickael Bourge ◽  
Fabrice Dumas ◽  
Olivier C. Martin ◽  
Matthieu Falque

2021 ◽  
Vol 25 (6) ◽  
pp. 661-668
Author(s):  
L. P. Malinovskaya ◽  
K. V. Tishakova ◽  
T. I. Bikchurina ◽  
A. Yu. Slobodchikova ◽  
N. Yu. Torgunakov ◽  
...  

Benefits and costs of meiotic recombination are a matter of discussion. Because recombination breaks allele combinations already tested by natural selection and generates new ones of unpredictable fitness, a high recombination rate is generally beneficial for the populations living in a fluctuating or a rapidly changing environment and costly in a stable environment. Besides genetic benefits and costs, there are cytological effects of recombination, both positive and negative. Recombination is necessary for chromosome synapsis and segregation. However, it involves a massive generation of double-strand DNA breaks, erroneous repair of which may lead to germ cell death or various mutations and chromosome rearrangements. Thus, the benefits of recombination (generation of new allele combinations) would prevail over its costs (occurrence of deleterious mutations) as long as the population remains sufficiently heterogeneous. Using immunolocalization of MLH1, a mismatch repair protein, at the synaptonemal complexes, we examined the number and distribution of recombination nodules in spermatocytes of two chicken breeds with high (Pervomai) and low (Russian Crested) recombination rates and their F1 hybrids and backcrosses. We detected negative heterosis for recombination rate in the F1 hybrids. Backcrosses to the Pervomai breed were rather homogenous and showed an intermediate recombination rate. The differences in overall recombination rate between the breeds, hybrids and backcrosses were mainly determined by the differences in the crossing over number in the seven largest macrochromosomes. The decrease in recombination rate in F1 is probably determined by difficulties in homology matching between the DNA sequences of genetically divergent breeds. The suppression of recombination in the hybrids may impede gene flow between parapatric populations and therefore accelerate their genetic divergence. 


2021 ◽  
Vol 55 (1) ◽  
Author(s):  
Ian R. Henderson ◽  
Kirsten Bomblies

Sex, as well as meiotic recombination between homologous chromosomes, is nearly ubiquitous among eukaryotes. In those species that use it, recombination is important for chromosome segregation during gamete production, and thus for fertility. Strikingly, although in most species only one crossover event per chromosome is required to ensure proper segregation, recombination rates vary considerably above this minimum and show variation within and among species. However, whether this variation in recombination is adaptive or neutral and what might shape it remain unclear. Empirical studies and theory support the idea that recombination is generally beneficial but can also have costs. Here, we review variation in genome-wide recombination rates, explore what might cause this, and discuss what is known about its mechanistic basis. We end by discussing the environmental sensitivity of meiosis and recombination rates, how these features may relate to adaptation, and their implications for a broader understanding of recombination rate evolution. Expected final online publication date for the Annual Review of Genetics, Volume 55 is November 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.


2018 ◽  
Vol 64 (4) ◽  
pp. 198-201 ◽  
Author(s):  
Jiwei Mao ◽  
Quanli Liu ◽  
Yuanzi Li ◽  
Jiuxia Yang ◽  
Xinhao Song ◽  
...  

Planta Medica ◽  
2016 ◽  
Vol 82 (05) ◽  
Author(s):  
C Avonto ◽  
AG Chittiboyina ◽  
D Rua ◽  
IA Khan

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