The effect of gamma radiation on recombination frequency in Caenorhabditis elegans

J. S. Kim; A. M. Rose

doi:10.1139/g87-079

The effect of gamma radiation on recombination frequency in Caenorhabditis elegans

Genome ◽

10.1139/g87-079 ◽

1987 ◽

Vol 29 (3) ◽

pp. 457-462 ◽

Cited By ~ 7

Author(s):

J. S. Kim ◽

A. M. Rose

Keyword(s):

Caenorhabditis Elegans ◽

Gamma Radiation ◽

Egg Production ◽

Radiation Treatment ◽

Recombination Frequency ◽

Gene Density ◽

Factors Affecting ◽

Group I ◽

High Gene ◽

Higher Doses

We have studied the effect of gamma radiation on recombination frequency for intervals across the cluster of linkage group I in Caenorhabditis elegans. Recombination frequency increased approximately twofold across the dpy-5–unc-13 interval after treatment with 2000 rads (1 rad = 10 mGy) of cobalt 60 gamma radiation. Several factors affecting the magnitude of the increase have been characterized. Recombination frequency increased more with higher doses of radiation. However, the increase in recombination frequency with increasing dose was accompanied by a reduced average number of progeny from radiation-treated individuals. The amount of the increase was affected by meiotic stage, age at the time of treatment (premeiotic), and radiation dose. The increase in recombination was detectable in the B brood and remained elevated for the remainder of egg production. X-chromosome nondisjunction was also increased by radiation treatment. A high frequency of the recombinant progeny produced with radiation treatment were sterile unlike their nonrecombinant siblings. When parameters affecting recombination frequency are held constant during treatment, chromosomal regions of high gene density on the meiotic map increased more (fourfold) than an adjacent region of low gene density (no increase). The greatest increase was across the dpy-14–unc-13 interval near the center of the gene cluster. These results may suggest that the physical length of DNA per map unit is greater within the cluster than outside. Key words: recombination, radiation, nondisjunction, map expansion, genetic map.

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Sex-related differences in crossing over in Caenorhabditis elegans.

Genetics ◽

10.1093/genetics/126.2.355 ◽

1990 ◽

Vol 126 (2) ◽

pp. 355-363

Author(s):

M C Zetka ◽

A M Rose

Keyword(s):

Caenorhabditis Elegans ◽

Maternal Age ◽

Elevated Temperatures ◽

Recombination Frequency ◽

Paternal Age ◽

Crossing Over ◽

Nematode Caenorhabditis Elegans ◽

Male Recombination ◽

Group I ◽

The Right

Abstract In the nematode Caenorhabditis elegans, hermaphrodite recombination has been characterized and is the basis of the genetic map used in this organism. In this study we have examined male recombination on linkage group I and have found it to be approximately one-third less than that observed in the hermaphrodite. This decrease was interval-dependent and nonuniform. We observed less recombination in the male in 5 out of 6 intervals examined, and no observable difference in one interval on the right end of LG I. Hermaphrodite recombination frequencies are the result of recombination in two germlines; oocyte and hermaphrodite spermatocytes. We have measured recombination in the oocyte and have found it to be approximately twofold lower than that calculated for hermaphrodite spermatocytes and not significantly different from the male spermatocyte frequency. Thus, recombination frequencies appear to be a function of gonad physiology rather than the sex of the germline. Evidence from experiments examining the effect of karyotype on recombination in males sexually transformed by the her-1 mutation into XO hermaphrodites (normally XX), suggests the sexual phenotype rather than genotype determines the recombination frequency characteristic of a particular sex. Hermaphrodite recombination is known to be affected by temperature, maternal age, and the rec-1 mutation. We have examined the effect of these parameters on recombination in the male and have found male recombination frequency increased with elevated temperatures and in the presence of Rec-1, and decreased with paternal age.

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

Genetics ◽

10.1093/genetics/106.1.109 ◽

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.

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MOLECULAR MAPPING OF A GENE CLUSTER FLANKING THE DROSOPHILA DOPA DECARBOXYLASE GENE

Genetics ◽

10.1093/genetics/106.4.679 ◽

1984 ◽

Vol 106 (4) ◽

pp. 679-694

Author(s):

Denise Gilbert ◽

Jay Hirsh ◽

T R F Wright

Keyword(s):

Gene Cluster ◽

Molecular Mapping ◽

Gene Density ◽

Dopa Decarboxylase ◽

Chromosomal Dna ◽

Potential Significance ◽

High Gene ◽

Complementation Groups ◽

High Gene Density

ABSTRACT Nine lethal complementation groups flanking the Drosophila Dopa decarboxylase (Ddc) gene, have been localized within 100 kb of cloned chromosomal DNA. Six of these complementation groups are within 23 kb of DNA, and all ten complementation groups, including Ddc, lie within 78-82 kb of DNA. The potential significance of this unusually high gene density is discussed.

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A High-Fecundity Aedine: Factors Affecting Egg Production of the Western Treehole Mosquito, Aedes Sierrensis (Diptera: Culicidae)

Journal of Medical Entomology ◽

10.1093/jmedent/22.2.220 ◽

1985 ◽

Vol 22 (2) ◽

pp. 220-225 ◽

Cited By ~ 31

Author(s):

William A. Hawley

Keyword(s):

Egg Production ◽

High Fecundity ◽

Factors Affecting ◽

Treehole Mosquito ◽

Aedes Sierrensis

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The role of Caenorhabditis elegans sex-determination homologs, Mi-sdc-1 and Mi-tra-1 in Meloidogyne incognita

European Journal of Plant Pathology ◽

10.1007/s10658-021-02335-3 ◽

2021 ◽

Author(s):

Anil Baniya ◽

Soumi Joseph ◽

Larry Duncan ◽

William Crow ◽

Tesfamariam Mengistu

Keyword(s):

Caenorhabditis Elegans ◽

Sex Determination ◽

Meloidogyne Incognita ◽

Egg Production ◽

Target Genes ◽

Parasitic Nematode ◽

Plant Parasitic Nematode ◽

Root Knot Nematode ◽

Model Free ◽

Plant Parasitic

AbstractSex determination is a key developmental event in all organisms. The pathway that regulates sexual fate has been well characterized at the molecular level in the model free-living nematode Caenorhabditis elegans. This study aims to gain a preliminary understanding of sex-determining pathways in a plant-parasitic nematode Meloidogyne incognita, and the extent to which the roles of the sex determination genes are conserved in a hermaphrodite species, C. elegans, and plant-parasitic nematode species, M. incognita. In this study, we targeted two sex-determining orthologues, sdc-1 and tra-1 from M. incognita using RNA interference (RNAi). RNAi was performed by soaking second-stage juveniles of M. incognita in a solution containing dsRNA of either Mi-tra-1or Mi-sdc-1 or both. To determine the effect of RNAi of the target genes, the juveniles treated with the dsRNA were inoculated onto a susceptible cultivar of cowpea grown in a nutrient pouch at 28 °C for 5 weeks. The development of the nematodes was analyzed at different time points during the growth period and compared to untreated controls. Our results showed that neither Mi-sdc-1 nor Mi-tra-1 have a significant role in regulating sexual fate in M. incognita. However, the silencing of Mi-sdc-1 significantly delayed maturity to adult females but did not affect egg production in mature females. In contrast, the downregulation of Mi-tra-1 transcript resulted in a significant reduction in egg production in both single and combinatorial RNAi-treated nematodes. Our results indicate that M. incognita may have adopted a divergent function for Mi-sdc-1 and Mi-tra-1distinct from Caenorhabditis spp. However, Mi-tra-1 might have an essential role in female fecundity in M. incognita and is a promising dsRNA target for root-knot nematode (RKN) management using host-delivered RNAi.

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Saturation Mapping of a Gene-Rich Recombination Hot Spot Region in Wheat

Genetics ◽

10.1093/genetics/154.2.823 ◽

2000 ◽

Vol 154 (2) ◽

pp. 823-835 ◽

Cited By ~ 12

Author(s):

Justin D Faris ◽

Karri M Haen ◽

Bikram S Gill

Keyword(s):

Positional Cloning ◽

Physical Map ◽

Hot Spot ◽

Chromosome Breakage ◽

Small Chromosome ◽

Gene Density ◽

Chromosome 5B ◽

High Gene ◽

The Many ◽

Recombination Hot Spots

AbstractPhysical mapping of wheat chromosomes has revealed small chromosome segments of high gene density and frequent recombination interspersed with relatively large regions of low gene density and infrequent recombination. We constructed a detailed genetic and physical map of one highly recombinant region on the long arm of chromosome 5B. This distally located region accounts for 4% of the physical size of the long arm and at least 30% of the recombination along the entire chromosome. Multiple crossovers occurred within this region, and the degree of recombination is at least 11-fold greater than the genomic average. Characteristics of the region such as gene order and frequency of recombination appear to be conserved throughout the evolution of the Triticeae. The region is more prone to chromosome breakage by gametocidal gene action than gene-poor regions, and evidence for genomic instability was implied by loss of gene collinearity for six loci among the homeologous regions. These data suggest that a unique level of chromatin organization exists within gene-rich recombination hot spots. The many agronomically important genes in this region should be accessible by positional cloning.

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