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 GENETIC CONTROL OF MEIOSIS IN RICE, ORYZA SATIVA L. III. EFFECT OF DS GENES ON GENETIC RECOMBINATION

Genetics ◽  
1984 ◽  
Vol 108 (3) ◽  
pp. 697-706
Author(s):  
Kunio Kitada ◽  
Takeshi Omura
Keyword(s):  
Oryza Sativa ◽  
Chiasma Frequency ◽  
Genetic Recombination ◽  
Recombination Frequency ◽  
Oryza Sativa L ◽  
The Other ◽  
Crossing Over ◽  
Homozygous Condition ◽  
Synaptonemal Complexes ◽  
The Mean

ABSTRACT The recombination frequency as influenced by five independent recessive ds genes was measured on three segments of different chromosomes of rice, Oryza sativa L. Each ds gene in the homozygous condition resulted in an almost equally reduced recombination frequency in the three segments. When the mean reduction in recombination frequency was related to the reduction of chiasma frequency, the five ds genes were divided into two types: in one type the reduction of chiasma frequency almost corresponded to the mean reduction of recombination frequency, and in the other the chiasma frequency was greatly reduced in comparison with the mean reduction of recombination frequency. Three of the five ds genes were found to belong to the former group. In both types, normal synaptonemal complexes were observed in pachytene cells homozygous for ds genes. This finding suggests that ds genes do not affect the formation of synaptonemal complexes which are regarded as the prerequisite structure for crossing over.

Concluding remarks

1977 ◽  
Vol 277 (955) ◽  
pp. 371-376 ◽  
Keyword(s):  
Genetic Recombination ◽  
Meiotic Behaviour ◽  
Chromosome Organization ◽  
Base Sequence ◽  
Crossing Over ◽  
Primary Target ◽  
Sequence Complexity ◽  
A Genome ◽  
Chromosome Alignment ◽  
Single Pattern

Professor Darlington opened the meeting by challenging us with the view that chromosomes made the laws of heredity, rather than heredity fashioning the organization of chromosomes. To keep this wheel of logic spinning, it may be said that chromosomes also made the process of meiosis and thus determined the laws of meiotic exchange. I choose this gambit because our discussions lent considerable emphasis to the view that chromosome complexity compels its own sets of distinctive, and perhaps varied, mechanisms to effect the ultimate event of molecular recombination. The complexity that leads molecular recombination to operate in elaborate meiotic moulds is not, it should be emphasized, base sequence complexity. On the contrary, sequence repeats and genetic homoeologies, though adding disproportionately little to the base sequence complexity of a genome, adds considerably to the complexity of effecting chromosome alignment and crossing over. How chromosomes of diverse genetic content manage that complexity and in the process mould the characteristics of meiotic behaviour has been the primary target of our deliberations. That no single pattern of meiotic conduct was perceived in consequence of the discussions, is to be expected. To the extent that genomes differ in various aspects of chromosome organization - and that they do is patent - the particulars of meiotic organization might also differ. Although a strong sentiment was occasionally expressed for a single universal process of meiosis, it is my opinion that sameness and universality may be mistakenly treated as synonyms. Universals provide for diversity; they do not impose sameness. The task of identifying universal threads among different meiotic fabrics is not a straightforward one. The ultimate act of genetic recombination offers no detailed guide to the routes by which it may be achieved. Indeed, it is the structure of the chromosome that dictates the route ; recombination only signals the direction.

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 Effect of Novel Rhythmic Physical Activities on Fundamental Movement Skills in 3- to 5-Year-Old Children

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Xin Hu ◽  
Gui-ping Jiang ◽  
Zhong-qiu Ji ◽  
Bo Pang ◽  
John Liu
Keyword(s):  
Motor Development ◽  
Repeated Measures ◽  
Physical Activities ◽  
Sensitive Period ◽  
Control Group ◽  
Movement Skills ◽  
Fundamental Movement Skills ◽  
Before And After ◽  
Movement Parameters ◽  
Practice Methods

Based on traditional rhythmic physical activities (TRPA), we created novel rhythmic physical activities (NRPA). The purpose of this study was to verify the effectiveness of NRPA in improving children’s fundamental movement skills (FMS). 289 children (135 boys, 154 girls) from 3 to 5 years old were randomly divided into an experimental group and a control group. Tools of Test of Gross Motor Development-2, Tekscan instrument, and balance beam were to assess children’s FMS. Two-way repeated measures ANOVA was used to analyze and compare the changes in the related parameters of locomotor, manipulative, and balance movement skills before and after intervention ( groups × time ). NRPA performed significantly better than TRPA from pre- to posttest for FMS. Furthermore, NRPA had significantly higher posttest scores than TRPA. Therefore, NRPA could effectively promote the development of children’s FMS due to the concept of the sensitive period of motor development, the variability of movement parameters, and the incomplete repeatability of practice methods.

scholarly journals Linkage relationships of markers on chromosome 17 of the house mouse

1975 ◽  
Vol 26 (2) ◽  
pp. 203-211 ◽  
Author(s):  
Graig Hammerberg ◽  
Jan Klein
Keyword(s):  
House Mouse ◽  
Chromosomal Region ◽  
Recombination Frequency ◽  
Genetic Distances ◽  
Chromosome 17 ◽  
Linkage Data ◽  
Crossing Over ◽  
The Right ◽  
Linkage Relationships ◽  
Important Marker

SUMMARYLinkage data for the following markers on chromosome 17 of the house mouse were obtained: centromere (marked by translocation R67), Brachyury (T), tufted (tf), H-2, and thin fur (thf). The markers were found to be arranged in that order in the genetic map and the combined genetic distances between individual markers were found to be as follows: Rb7…T, 4·5 cM; T…tf, 5·8 cM; tf…H-2, 5·0 cM; H-2…thf, 15·1 cM. The localization of the thf locus on the non-centromeric side of the H-2 complex provides an important marker for this arm of chromosome 17. The map distances in the centromeric portion of chromosome 17 changed drastically in the presence of various t factors. These factors strongly reduce the recombination frequency in the T…tf and tf…H-2 intervals and this crossing-over suppression is most likely responsible for the linkage disequilibrium between t and H-2 reported earlier. Recombinants involving a t chromosome but occurring to the right of the H-2 complex do not change the properties of t factors suggesting that all determinants responsible for the t phenotype are located in the chromosomal region between T and tf (H-2).

High resolution map around the vrs1 locus controlling two- and six-rowed spike in barley, Hordeum vulgare

Genome ◽  
1999 ◽  
Vol 42 (2) ◽  
pp. 248-253 ◽  
Author(s):  
Takao Komatsuda ◽  
Wenbin Li ◽  
Fumio Takaiwa ◽  
Seibi Oka
Keyword(s):  
Hordeum Vulgare ◽  
Mapping Population ◽  
Recombination Frequency ◽  
Linkage Study ◽  
Linkage Data ◽  
Published Data ◽  
Crossing Over ◽  
Lateral Spikelet ◽  
Significant Difference ◽  
High Resolution Map

The vrs1 (formerly v) locus in the long arm of chromosome 2H controls lateral spikelet development in barley. The vrs1 locus was mapped by backcross-derived lines that consisted of 373 BC7F1 plants and 278 BC6F2 plants. The linkage study indicated that MWG801, CMNA-38/700, cMWG699, vrs1 and MWG865 exist in the order listed, with map distances of 3.1, 0.4, 0.1, and 0.9 centimorgans (cM), respectively. Recombination in female and male meiocytes showed no significant difference within this region. In a neighboring region between MWG865 and MWG503, the recombination frequency was higher in female than male meiocytes in one mapping population. The combined linkage data obtained from this study were compared with published data, and genotype-specific suppression of crossing-over was not evident in the vrs1 region.Key words: vrs1 locus (two- vs. six-rowed), molecular marker, recombination, backcross, Hordeum vulgare.

scholarly journals Systematic Mutagenesis of the Saccharomyces cerevisiae MLH1 Gene Reveals Distinct Roles for Mlh1p in Meiotic Crossing Over and in Vegetative and Meiotic Mismatch Repair

2003 ◽  
Vol 23 (3) ◽  
pp. 873-886 ◽  
Author(s):  
Juan Lucas Argueso ◽  
Amanda Wraith Kijas ◽  
Sumeet Sarin ◽  
Julie Heck ◽  
Marc Waase ◽  
...  
Keyword(s):  
Mismatch Repair ◽  
Ternary Complex ◽  
Genetic Recombination ◽  
Crossing Over ◽  
Wild Type ◽  
Dna Mismatch ◽  
Biochemical Assays ◽  
Postmeiotic Segregation ◽  
New Alleles

ABSTRACT In eukaryotic cells, DNA mismatch repair is initiated by a conserved family of MutS (Msh) and MutL (Mlh) homolog proteins. Mlh1 is unique among Mlh proteins because it is required in mismatch repair and for wild-type levels of crossing over during meiosis. In this study, 60 new alleles of MLH1 were examined for defects in vegetative and meiotic mismatch repair as well as in meiotic crossing over. Four alleles predicted to disrupt the Mlh1p ATPase activity conferred defects in all functions assayed. Three mutations, mlh1-2, -29, and -31, caused defects in mismatch repair during vegetative growth but allowed nearly wild-type levels of meiotic crossing over and spore viability. Surprisingly, these mutants did not accumulate high levels of postmeiotic segregation at the ARG4 recombination hotspot. In biochemical assays, Pms1p failed to copurify with mlh1-2, and two-hybrid studies indicated that this allele did not interact with Pms1p and Mlh3p but maintained wild-type interactions with Exo1p and Sgs1p. mlh1-29 and mlh1-31 did not alter the ability of Mlh1p-Pms1p to form a ternary complex with a mismatch substrate and Msh2p-Msh6p, suggesting that the region mutated in these alleles could be responsible for signaling events that take place after ternary complex formation. These results indicate that mismatches formed during genetic recombination are processed differently than during replication and that, compared to mismatch repair functions, the meiotic crossing-over role of MLH1 appears to be more resistant to mutagenesis, perhaps indicating a structural role for Mlh1p during crossing over.

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