Crossing over does occur in males of Drosophila ananassae from natural populations

Spontaneous crossing over in males of Drosophila ananassae has been well demonstrated using F1 individuals from crosses between marker stocks and wild type strains. However, the question of its occurrence in males from natural populations remained open. Here we present the cytological evidence that crossing over does occur in males of D. ananassae from two Brazilian populations, sampled nearly 21 years apart, and in two recently sampled populations, one from Indonesia and one from Okinawa, Japan. Cytological analysis of meiosis in males collected from nature and in sons of females from the same population inseminated in nature revealed the presence of chiasmata, inversion chiasmata, and isosite chromosome breakages in the diplotene cells in all sampled populations. These data demonstrate that reciprocal and nonreciprocal exchanges and chromosome breakages, previously reported as related events of male crossing over, do occur at variable frequencies among males from natural populations.

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Complete absence of linkage disequilibrium between enzyme loci in natural populations of Drosophila ananassae

Genetika ◽

10.2298/gensr1401227k ◽

2014 ◽

Vol 46 (1) ◽

pp. 227-234 ◽

Cited By ~ 3

Author(s):

Sanjay Kumar ◽

A.K. Singh

Keyword(s):

Linkage Disequilibrium ◽

Natural Populations ◽

Drosophila Ananassae ◽

Crossing Over ◽

Enzyme Loci ◽

Random Occurrence

Linkage disequilibrium has been studied among three linked enzyme loci of second chromosome of D. ananassae collected from five natural populations. Each of the three enzyme loci, that is Acph1, Acph 2 and Xdh was represented by two distinct alleles and in three genotypic forms. Thus nine genotypic combinations were recorded for each enzyme pair. The results clearly show absence of non-random occurrence of different genotypic combinations in all the populations studied. The occurrence of all possible genotypic combinations indicates enough frequency of crossing over among these enzyme loci. The absence of linkage disequilibrium in this study thus indicates that selection did not play any role and free recombination among the genes resulted random occurrence of all combinations.

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Comparison of the mitotic karyotypes of Ceratitis capitata, Ceratitis rosa, and Trirhithrum coffeae (Diptera: Tephritidae) by C-banding and FISH

Genome ◽

10.1139/g96-111 ◽

1996 ◽

Vol 39 (5) ◽

pp. 884-889 ◽

Cited By ~ 13

Author(s):

Ute Willhoeft ◽

Gerald Franz

Keyword(s):

Y Chromosome ◽

Sex Chromosomes ◽

Ceratitis Capitata ◽

Natural Populations ◽

Fruit Fly ◽

Deletion Mapping ◽

Wild Type ◽

C Banding ◽

Y Chromosomes ◽

Type Strains

The sex chromosomes of the tephritid fruit fly Ceratitis capitata (Wiedemann) are heteromorphic. The male-determining region was located on the Y chromosome by deletion mapping using unbalanced offspring from several translocation strains. In addition, we showed that only 15% of the Y chromosome is required for male determination and male fertility. Based on this result, we expected to find Y-chromosomal length polymorphism in natural populations. Using fluorescence in situ hybridization with two repetitive DNA probes that label the Y chromosome, no obvious size differences were detected in seven wild-type strains and three mutant strains. As the medfly is probably of East African origin, we also analyzed two wild-type strains established recently from pupae sampled in Kenya. The Y chromosomes show a polymorphism in the hybridization pattern of a repetitive Y-specific medfly clone. However, the overall size of the Y chromosome is similar to that of the other strains. Besides C. capitata, the tephritid fruit flies Ceratitis (Pterandrus) rosa Karsch and Trirhithrum coffeae Bezzi also emerged from pupae sampled in Kenya. Their karyotype was analyzed by C-banding. Furthermore, the ribosomal genes were mapped to the sex chromosomes in these two species. Key words : Ceratitis capitata, Tephritidae, C-Banding, FISH, rDNA.

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Chiasmata and chromosome breakages are related to crossing over in Drosophila ananassae males

Genome ◽

10.1139/g06-106 ◽

2006 ◽

Vol 49 (11) ◽

pp. 1374-1383 ◽

Cited By ~ 3

Author(s):

Beatriz Goñi ◽

Muneo Matsuda ◽

Yoshiko N. Tobari

Keyword(s):

Chromosome Pairing ◽

Chiasma Frequency ◽

Genetic Factors ◽

Genetic Recombination ◽

Paracentric Inversion ◽

Drosophila Ananassae ◽

Crossing Over ◽

Low Frequencies ◽

Genetic Crossing ◽

Chromosome Breakages

A cytogenetic analysis of male crossing over in Drosophila ananassae revealed that cytological exchanges resulted in genetic crossing over, and that chiasma frequency and the genetic recombination correlated positively in chromosomes 2 and 3. Furthermore, the frequency of chromosome breakages correlated positively with chiasma frequency. Paracentric inversion heterozygosity had no detectable influence on the chromosome pairing or exchange events within the inversion loop at meiosis. Scoring of the chiasma demonstrated that males homozygous for the previously mapped enhancers of male crossing over had low frequencies of chiasmata, whereas higher frequencies of chiasmata were observed in males heterozygous for enhancers. The results presented here indicate that the genetic factors controlling male crossing over are involved in the origin of chromosome breakages and in exchange events.

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Male recombination in Brazilian populations of Drosophila ananassae

Genome ◽

10.1139/gen-2015-0169 ◽

2016 ◽

Vol 59 (7) ◽

pp. 493-500 ◽

Cited By ~ 1

Author(s):

Beatriz Goñi ◽

Muneo Matsuda ◽

Yoshiko N. Tobari

Keyword(s):

Genetic Control ◽

Genetic Factors ◽

Regional Distribution ◽

High Variability ◽

Drosophila Ananassae ◽

Crossing Over ◽

Male Recombination ◽

Spontaneous Recombination ◽

Recombination Value ◽

Brazilian Populations

With few exceptions, spontaneous crossing over does not normally occur in male Drosophila. Drosophila ananassae males show considerable amounts of crossing over. In wild males of D. ananassae from Asian (2008) and Brazilian populations (1986 and 2007) variable frequencies of meiotic crossing over, estimated from chiasmata counts, suggested the existence of factors controlling male crossing over in these populations. To corroborate for such prediction, we present data on spontaneous recombination in F1 males of D. ananassae heterozygous for chromosomes of the same Brazilian populations (1986) and marker chromosomes using three testers stocks. Mean recombination value was low, although high variability existed between individual frequencies. Recombination frequencies between lines in each tester stock were not significantly different, excepting when the 3ple-px and 3ple-cy testers were compared (p < 0.05). These two testers differ in respect to the regional distribution of crossovers. The occurrence of recombination in chromosomes 2 and 3 in F1 males tested with e65 se; bri ru was not related, suggesting they are under independent genetic control. Our data are consistent with proposed genetic factors controlling male crossing over in the tester stocks and to the presence of enhancers and suppressors of male crossing over segregating in the Brazilian populations (1986).

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Effect of Selection on Crossing over in the Males of Drosophila ananassae

The American Naturalist ◽

10.1086/282157 ◽

1961 ◽

Vol 95 (880) ◽

pp. 57-59 ◽

Cited By ~ 16

Author(s):

A. S. Mukherjee

Keyword(s):

Drosophila Ananassae ◽

Crossing Over

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The Budding Yeast Msh4 Protein Functions in Chromosome Synapsis and the Regulation of Crossover Distribution

Genetics ◽

10.1093/genetics/158.3.1013 ◽

2001 ◽

Vol 158 (3) ◽

pp. 1013-1025 ◽

Cited By ~ 7

Author(s):

Janet E Novak ◽

Petra B Ross-Macdonald ◽

G Shirleen Roeder

Keyword(s):

Mismatch Repair ◽

Budding Yeast ◽

Null Mutation ◽

Crossing Over ◽

Wild Type ◽

Crossover Interference ◽

Meiotic Chromosomes ◽

Chromosome Synapsis ◽

Protein Functions ◽

Or Gene

AbstractThe budding yeast MSH4 gene encodes a MutS homolog produced specifically in meiotic cells. Msh4 is not required for meiotic mismatch repair or gene conversion, but it is required for wild-type levels of crossing over. Here, we show that a msh4 null mutation substantially decreases crossover interference. With respect to the defect in interference and the level of crossing over, msh4 is similar to the zip1 mutant, which lacks a structural component of the synaptonemal complex (SC). Furthermore, epistasis tests indicate that msh4 and zip1 affect the same subset of meiotic crossovers. In the msh4 mutant, SC formation is delayed compared to wild type, and full synapsis is achieved in only about half of all nuclei. The simultaneous defects in synapsis and interference observed in msh4 (and also zip1 and ndj1/tam1) suggest a role for the SC in mediating interference. The Msh4 protein localizes to discrete foci on meiotic chromosomes and colocalizes with Zip2, a protein involved in the initiation of chromosome synapsis. Both Zip2 and Zip1 are required for the normal localization of Msh4 to chromosomes, raising the possibility that the zip1 and zip2 defects in crossing over are indirect, resulting from the failure to localize Msh4 properly.

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Identification ofvib-1, a Locus Involved in Vegetative Incompatibility Mediated byhet-cinNeurospora crassa

Genetics ◽

10.1093/genetics/162.1.89 ◽

2002 ◽

Vol 162 (1) ◽

pp. 89-101 ◽

Cited By ~ 6

Author(s):

Qijun Xiang ◽

N Louise Glass

Keyword(s):

Acid Phosphatase ◽

Recognition System ◽

Deletion Mutants ◽

Wild Type ◽

Vegetative Incompatibility ◽

Death Rates ◽

Self Recognition ◽

Allelic Differences ◽

Native Gel ◽

Type Strains

AbstractA non-self-recognition system called vegetative incompatibility is ubiquitous in filamentous fungi and is genetically regulated by het loci. Different fungal individuals are unable to form viable heterokaryons if they differ in allelic specificity at a het locus. To identify components of vegetative incompatibility mediated by allelic differences at the het-c locus of Neurospora crassa, we isolated mutants that suppressed phenotypic aspects of het-c vegetative incompatibility. Three deletion mutants were identified; the deletions overlapped each other in an ORF named vib-1 (vegetative incompatibility blocked). Mutations in vib-1 fully relieved growth inhibition and repression of conidiation conferred by het-c vegetative incompatibility and significantly reduced hyphal compartmentation and death rates. The vib-1 mutants displayed a profuse conidiation pattern, suggesting that VIB-1 is a regulator of conidiation. VIB-1 shares a region of similarity to PHOG, a possible phosphate nonrepressible acid phosphatase in Aspergillus nidulans. Native gel analysis of wild-type strains and vib-1 mutants indicated that vib-1 is not the structural gene for nonrepressible acid phosphatase, but rather may regulate nonrepressible acid phosphatase activity.

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UNEQUAL CROSSING OVER AT THE rRNA TANDON AS A SOURCE OF QUANTITATIVE GENETIC VARIATION IN DROSOPHILA

Genetics ◽

10.1093/genetics/95.3.727 ◽

1980 ◽

Vol 95 (3) ◽

pp. 727-742 ◽

Cited By ~ 1

Author(s):

R Frankham ◽

D A Briscoe ◽

R K Nurthen

Keyword(s):

Genetic Variation ◽

Selection Response ◽

Crossing Over ◽

Wild Type ◽

X Chromosomes ◽

Unequal Crossing Over ◽

Quantitative Genetic ◽

Y Chromosomes ◽

Homozygous Line ◽

Minimum Estimate

ABSTRACT Abdominal bristle selection lines (three high and three low) and controls were founded from a marked homozygous line to measure the contribution of sex-linked "mutations" to selection response. Two of the low lines exhibited a period of rapid response to selection in females, but not in males. There were corresponding changes in female variance, in heritabilities in females, in the sex ratio (a deficiency of females) and in fitness, as well as the appearance of a mutant phenotype in females of one line. All of these changes were due to bb alleles (partial deficiencies for the rRNA tandon) in the X chromosomes of these lines, while the Y chromosomes remained wild-type bb+. We argue that the bb alleles arose by unequal crossing over in the rRNA tandon.—A prediction of this hypothesis is that further changes can occur in the rRNA tandon as selection is continued. This has now been shown to occur.—Our minimum estimate of the rate of occurrence of changes at the rRNA tandon is 3 × 10-4. As this is substantially higher than conventional mutation rates, the questions of the mechanisms and rates of origin of new quantitative genetic variation require careful re-examination.

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HET-E and HET-D Belong to a New Subfamily of WD40 Proteins Involved in Vegetative Incompatibility Specificity in the Fungus Podospora anserina

Genetics ◽

10.1093/genetics/161.1.71 ◽

2002 ◽

Vol 161 (1) ◽

pp. 71-81

Author(s):

Eric Espagne ◽

Pascale Balhadère ◽

Marie-Louise Penin ◽

Christian Barreau ◽

Béatrice Turcq

Keyword(s):

Genetic Difference ◽

Podospora Anserina ◽

Wild Type ◽

Incompatible Interaction ◽

Vegetative Incompatibility ◽

Repeat Domain ◽

Upper Face ◽

E1a Gene ◽

Type Strains ◽

Wd40 Repeats

Abstract Vegetative incompatibility, which is very common in filamentous fungi, prevents a viable heterokaryotic cell from being formed by the fusion of filaments from two different wild-type strains. Such incompatibility is always the consequence of at least one genetic difference in specific genes (het genes). In Podospora anserina, alleles of the het-e and het-d loci control heterokaryon viability through genetic interactions with alleles of the unlinked het-c locus. The het-d2Y gene was isolated and shown to have strong similarity with the previously described het-e1A gene. Like the HET-E protein, the HET-D putative protein displayed a GTP-binding domain and seemed to require a minimal number of 11 WD40 repeats to be active in incompatibility. Apart from incompatibility specificity, no other function could be identified by disrupting the het-d gene. Sequence comparison of different het-e alleles suggested that het-e specificity is determined by the sequence of the WD40 repeat domain. In particular, the amino acids present on the upper face of the predicted β-propeller structure defined by this domain may confer the incompatible interaction specificity.

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