scholarly journals Selection by parasites may increase host recombination frequency

2005 ◽  
Vol 1 (2) ◽  
pp. 193-195 ◽  
Author(s):  
O Fischer ◽  
P Schmid-Hempel
Keyword(s):  
Recombination Frequency

scholarly journals Interplay between Pds5 and Rec8 in regulating chromosome axis length and crossover frequency

2021 ◽  
Vol 7 (11) ◽  
pp. eabe7920
Author(s):  
Meihui Song ◽  
Binyuan Zhai ◽  
Xiao Yang ◽  
Taicong Tan ◽  
Ying Wang ◽  
...  
Keyword(s):  
Recombination Frequency ◽  
Crossover Frequency ◽  
Wild Type ◽  
Protein Levels ◽  
Homolog Pairing ◽  
Meiotic Chromosomes ◽  
Homologous Chromosome Pairing ◽  
Axis Length ◽  
Chromosome Axis

Meiotic chromosomes have a loop/axis architecture, with axis length determining crossover frequency. Meiosis-specific Pds5 depletion mutants have shorter chromosome axes and lower homologous chromosome pairing and recombination frequency. However, it is poorly understood how Pds5 coordinately regulates these processes. In this study, we show that only ~20% of wild-type level of Pds5 is required for homolog pairing and that higher levels of Pds5 dosage-dependently regulate axis length and crossover frequency. Moderate changes in Pds5 protein levels do not explicitly impair the basic recombination process. Further investigations show that Pds5 does not regulate chromosome axes by altering Rec8 abundance. Conversely, Rec8 regulates chromosome axis length by modulating Pds5. These findings highlight the important role of Pds5 in regulating meiosis and its relationship with Rec8 to regulate chromosome axis length and crossover frequency with implications for evolutionary adaptation.

scholarly journals Simplified All-In-One CRISPR-Cas9 Construction for Efficient Genome Editing in Cryptococcus Species

2021 ◽  
Vol 7 (7) ◽  
pp. 505
Author(s):  
Ping Zhang ◽  
Yu Wang ◽  
Chenxi Li ◽  
Xiaoyu Ma ◽  
Lan Ma ◽  
...  
Keyword(s):  
Genome Editing ◽  
Fungal Pathogens ◽  
Gene Editing ◽  
Recombination Frequency ◽  
Target Sequence ◽  
Widespread Application ◽  
Genetic Studies ◽  
Efficient Gene ◽  
Cryptococcus Species ◽  
Overlap Pcr

Cryptococcus neoformans and Cryptococcus deneoformans are opportunistic fungal pathogens found worldwide that are utilized to reveal mechanisms of fungal pathogenesis. However, their low homologous recombination frequency has greatly encumbered genetic studies. In preliminary work, we described a ‘suicide’ CRISPR-Cas9 system for use in the efficient gene editing of C. deneoformans, but this has not yet been used in the C. neoformans strain. The procedures involved in constructing vectors are time-consuming, whether they involve restriction enzyme-based cloning of donor DNA or the introduction of a target sequence into the gRNA expression cassette via overlap PCR, as are sophisticated, thus impeding their widespread application. Here, we report the optimized and simplified construction method for all-in-one CRISPR-Cas9 vectors that can be used in C. neoformans and C. deneoformans strains respectively, named pNK003 (Genbank: MW938321) and pRH003 (Genbank: KX977486). Taking several gene manipulations as examples, we also demonstrate the accuracy and efficiency of the new simplified all-in-one CRISPR-Cas9 genome editing tools in both Serotype A and Serotype D strains, as well as their ability to eliminate Cas9 and gDNA cassettes after gene editing. We anticipate that the availability of new vectors that can simplify and streamline the technical steps for all-in-one CRISPR-Cas9 construction could accelerate genetic studies of the Cryptococcus species.

scholarly journals GENETIC LINKAGE IN THE HORSE. II. DISTRIBUTION OF MALE RECOMBINATION ESTIMATES AND THE INFLUENCE OF AGE, BREED AND SEX ON RECOMBINATION FREQUENCY

Genetics ◽  
1984 ◽  
Vol 106 (1) ◽  
pp. 109-122
Author(s):  
Leif Andersson ◽  
Kaj Sandberg
Keyword(s):  
Genetic Linkage ◽  
Recombination Frequency ◽  
Age Effect ◽  
Significant Heterogeneity ◽  
Male Recombination ◽  
Male And Female ◽  
Factors Affecting ◽  
Individual Male ◽  
Breed Differences ◽  
Age And Sex

ABSTRACT n the present study an extensive amount of data, comprising more than 30,000 offspring in total, was analyzed to evaluate the influence of age and sex on the recombination frequency in the K-PGD segment of the equine linkage group (LG) I and the influence of age, breed and sex on recombination in the Al-Es segment of LG II. A highly significant sex difference is reported for both segments. Male and female recombination values in the K-PGD segment were estimated at 25.8 ± 0.8 and 33.3 ± 2.5%, respectively. Similarly, recombination was less frequent in the male (36.6 ± 0.7%) than in the female (46.6 ± 1.2%) in the Al-Es segment. Comparison of data from two Swedish horse breeds revealed no significant breed differences in either sex for recombination in the Al-Es segment. No evidence of an age effect was found in any segment or sex. The distribution of individual male recombination estimates was also investigated, and a significant heterogeneity among stallions was revealed in the K-PGD segment. The results are discussed in relation to previous studies on factors affecting recombination in mammals.

scholarly journals Increase of TCR Vβ Accessibility within Eβ Regulatory Region Influences its Recombination Frequency But Not Allelic Exclusion

2003 ◽  
Vol 171 (2) ◽  
pp. 829-835 ◽  
Author(s):  
Makoto Senoo ◽  
Lili Wang ◽  
Daisuke Suzuki ◽  
Naoki Takeda ◽  
Yoichi Shinkai ◽  
...  
Keyword(s):  
Recombination Frequency ◽  
Regulatory Region ◽  
Allelic Exclusion

GENETIC RECOMBINATION IN SEXUAL CROSSES OF PHYCOMYCES

Genetics ◽  
1975 ◽  
Vol 80 (3) ◽  
pp. 445-462
Author(s):  
A P Eslava ◽  
M I Alvarez ◽  
Patricia V Burke ◽  
M Delbrück
Keyword(s):  
Mating Type ◽  
Genetic Recombination ◽  
Recombination Frequency ◽  
Intragenic Recombination ◽  
Phycomyces Blakesleeanus ◽  
Sexual Crosses ◽  
Color Marker ◽  
Three Factor

ABSTRACT Sexual crosses between strains of Phycomyces blakesleeanus, involving three auxotrophic and one color marker and yielding a high proportion of zygospore germination, are described. Samples of 20-40 germ spores from 311 individual fertile germ sporangia originating from five two-factor and three three-factor crosses were characterized. The results show: (1) absence of any contribution of apogamic nuclei to the progeny, (2) confirmation of Burgeff's conjecture that the germ spores of any germ sporangium in most cases derive from one meiosis. In a cross involving two allelic markers the analysis of 175 pooled germ sporangia suggests an intragenic recombination frequency of 0.6%. All other factor combinations tested are unlinked. The bulk of the germ spores are homokaryotic. However, a small portion (4%) are heterokaryotic with respect to mating type.

scholarly journals Construction of a Genetic Linkage Map in Tetraploid Species Using Molecular Markers

Genetics ◽  
2001 ◽  
Vol 157 (3) ◽  
pp. 1369-1385 ◽  
Author(s):  
Z W Luo ◽  
C A Hackett ◽  
J E Bradshaw ◽  
J W McNicol ◽  
D Milbourne
Keyword(s):  
Molecular Markers ◽  
Linkage Map ◽  
Recombination Frequency ◽  
Simulated Data ◽  
Likelihood Estimation ◽  
Lod Score ◽  
Data Set ◽  
Independent Segregation ◽  
The Em Algorithm ◽  
Small Set

Abstract This article presents methodology for the construction of a linkage map in an autotetraploid species, using either codominant or dominant molecular markers scored on two parents and their full-sib progeny. The steps of the analysis are as follows: identification of parental genotypes from the parental and offspring phenotypes; testing for independent segregation of markers; partition of markers into linkage groups using cluster analysis; maximum-likelihood estimation of the phase, recombination frequency, and LOD score for all pairs of markers in the same linkage group using the EM algorithm; ordering the markers and estimating distances between them; and reconstructing their linkage phases. The information from different marker configurations about the recombination frequency is examined and found to vary considerably, depending on the number of different alleles, the number of alleles shared by the parents, and the phase of the markers. The methods are applied to a simulated data set and to a small set of SSR and AFLP markers scored in a full-sib population of tetraploid potato.

Genetic Recombination in Coprinus

1970 ◽  
Vol 6 (3) ◽  
pp. 669-678
Author(s):  
B. C. LU
Keyword(s):  
Fruiting Body ◽  
Temperature Effects ◽  
Cold Shock ◽  
Genetic Recombination ◽  
Recombination Frequency ◽  
Temperature Treatment ◽  
Sensitive Period ◽  
Crossing Over ◽  
Synaptinemal Complex ◽  
Before And After

The frequency of genetic recombination in Coprinus lagopus may be modified by heat and cold shock. By removal of samples from a fruiting body before and after temperature treatment, it is possible to study the ultrastructure of chromosomes at the time recombination frequency (between den+ x +me-1) can be modified. The sensitive period for temperature effects and, therefore, probably the time of crossing over, commences with the formation of the synaptinemal complex (S.C.) and ends with its disappearance, i.e. during the entire existence of the S.C. It is concluded that recombination is an event subsequent to the formation of the S.C. and is independent of the process of its formation. It is suggested that the event takes place at the synaptic centre.

scholarly journals Correction to ‘Variation in recombination frequency and distribution across eukaryotes: patterns and processes’

2017 ◽  
Vol 373 (1739) ◽  
pp. 20170360 ◽  
Author(s):  
Jessica Stapley ◽  
Philine G. D. Feulner ◽  
Susan E. Johnston ◽  
Anna W. Santure ◽  
Carole M. Smadja
Keyword(s):  
Recombination Frequency ◽  
Patterns And Processes
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