scholarly journals SUPPRESSOR SYSTEMS OF SEGREGATION DISTORTER (SD) CHROMOSOMES IN NATURAL POPULATIONS OF DROSOPHILA MELANOGASTER

Genetics ◽  
1984 ◽  
Vol 106 (2) ◽  
pp. 279-292
Author(s):  
Yuichiro Hiraizumi ◽  
Anita M Thomas
Keyword(s):  
North Carolina ◽  
Drosophila Melanogaster ◽  
Chromosome Segregation ◽  
Natural Populations ◽  
Low Frequencies ◽  
X Chromosomes ◽  
High Frequencies ◽  
Heterozygous Male ◽  
Segregation Distorter ◽  
Carolina Population

ABSTRACT Several natural populations of D. melanogaster were investigated for the presence (or absence) of the Segregation Distorter (SD) chromosomes and their suppressor systems. The SD chromosomes were found, at frequencies of a few percent, in two independent samples taken in different years from a Raleigh, North Carolina, population, whereas no SD chromosomes were found in samples collected from several populations in Texas. The populations in these localities were found to contain suppressor X chromosomes in high frequencies (75% or higher). They also contained relatively low frequencies of partial suppressor or insensitive second chromosomes of varying degrees, but completely insensitive second chromosomes were practically absent in all populations examined. The frequencies of suppressor X chromosomes, as well as those of the partially insensitive or suppressor second chromosomes, were the same among the populations investigated. This suggests the possibility that the development of a suppressor system of SD in a population could be independent of the presence of an SD chromosome. Segregation distortion appeared to be occurring in natural genetic backgrounds, but the degree of distortion varied among males of different genotypes. There were many instances in which the SD chromosomes showed transmission frequencies from their heterozygous male parents that were smaller than 0.6 and, in several cases, even smaller than 0.5. The presence of a recessive suppressor, or suppressors, of SD in natural populations was suggested.

scholarly journals Genetic Variation in Rates of Nondisjunction: Association of Two Naturally Occurring Polymorphisms in the Chromokinesin nod With Increased Rates of Nondisjunction in Drosophila melanogaster

Genetics ◽  
1999 ◽  
Vol 152 (4) ◽  
pp. 1605-1614 ◽  
Author(s):  
Michael E Zwick ◽  
Jennifer L Salstrom ◽  
Charles H Langley
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Variation ◽  
Chromosome Segregation ◽  
Natural Populations ◽  
Intermediate Frequency ◽  
Female Meiosis ◽  
X Chromosomes ◽  
Naturally Occurring ◽  
High Level ◽  
Female Specific

Abstract Genetic variation in nondisjunction frequency among X chromosomes from two Drosophila melanogaster natural populations is examined in a sensitized assay. A high level of genetic variation is observed (a range of 0.006-0.241). Two naturally occurring variants at the nod locus, a chromokinesin required for proper achiasmate chromosome segregation, are significantly associated with an increased frequency of nondisjunction. Both of these polymorphisms are found at intermediate frequency in widely distributed natural populations. To account for these observations, we propose a general model incorporating unique opportunities for meiotic drive during female meiosis. The oötid competition model can account for both high mean rates of female-specific nondisjunction in Drosophila and humans as well as the standing genetic variation in this critical fitness character in natural populations.

scholarly journals Enzyme null alleles in natural populations of Drosophila melanogaster: Frequencies in a North Carolina population

1980 ◽  
Vol 77 (2) ◽  
pp. 1091-1095 ◽  
Author(s):  
R. A. Voelker ◽  
C. H. Langley ◽  
A. J. L. Brown ◽  
S. Ohnishi ◽  
B. Dickson ◽  
...  
Keyword(s):  
North Carolina ◽  
Drosophila Melanogaster ◽  
Natural Populations ◽  
Null Alleles ◽  
Carolina Population

scholarly journals NULL ALLELE FREQUENCIES AT ALLOZYME LOCI IN NATURAL POPULATIONS OF DROSOPHILA MELANOGASTER

Genetics ◽  
1981 ◽  
Vol 99 (1) ◽  
pp. 151-156
Author(s):  
Charles H Langley ◽  
Robert A Voelker ◽  
Andrew J Leigh Brown ◽  
Seido Ohnishi ◽  
Barbara Dickson ◽  
...  
Keyword(s):  
North Carolina ◽  
Drosophila Melanogaster ◽  
Null Allele ◽  
Natural Populations ◽  
Allele Frequencies ◽  
Null Alleles ◽  
Carolina Population ◽  
The Mean ◽  
Allozyme Loci ◽  
Two Populations

ABSTRACT We have sampled a London population of Drosophila melanogaster for null alleles at twenty-five allozyme loci. The same loci and biochemical techniques were used as in our previous survey of a North Carolina population (Voelker et al. 1980). This second survey is completely concordant with the first. No nulls were detected among the five X-linked loci. The mean frequency of nulls at the twenty autosomal loci was 0.0023. Although there is significant interlocus heterogeneity, the two populations appear to have the same frequencies at each locus. This suggests that null alleles at these allozyme loci are in mutation-selection balance, and we estimate the average heterozygous effect of an allozyme null to be 0.0015. Consideration of allozyme null-allele frequencies, the effects of allozyme null alleles on viability and fertility and the generally greater amount of genetic variability at allozyme loci determined by electrophoresis lead us to doubt the validity of generalizing from allozyme data to the whole genome.

scholarly journals Insertion-deletion variation at the yellow-achaete-scute region in two natural populations of Drosophila melanogaster

1989 ◽  
Vol 53 (1) ◽  
pp. 7-15 ◽  
Author(s):  
Robin N. Beech ◽  
Andrew J. Leigh Brown
Keyword(s):  
North Carolina ◽  
Drosophila Melanogaster ◽  
Natural Populations ◽  
The North ◽  
Restriction Sites ◽  
Dna Insertion ◽  
Carolina Population ◽  
Element Evolution ◽  
High Level ◽  
Transposable Genetic Elements

SummaryWe have surveyed the region of the X chromosome of Drosophila melanogaster which encodes the yellow, achaete and scute genes for restriction map variation. Two natural populations, one from North Carolina, U.S.A. and the other from southern Spain were screened for variation at about 70 restriction sites and for variation due to DNA insertion or deletion events in 120 kilobases of DNA. Mean heterozygosity per nucleotide was estimated to be 0·0024 and 15 large insertions were found in the 49 chromosomes screened. Extensive disequilibrium between polymorphic sites was found across much of the region in the North Carolina population. The frequency of large insertions, which usually correspond to transposable genetic elements, is significantly lower than has been observed in autosomal regions of the genome. This is predicted for X-linked loci by certain models of transposable element evolution, where copy number is restricted by virtue of the recessive deleterious effects of the insertions. Our results appear to support such models. The deficiency of insertions may in this case be enhanced by hitch-hiking effects arising from the high level of disequilibrium.

scholarly journals The Regulatory Properties of Autonomous Subtelomeric P Elements Are Sensitive to a Suppressor of variegation in Drosophila melanogaster

Genetics ◽  
1996 ◽  
Vol 143 (4) ◽  
pp. 1663-1674 ◽  
Author(s):  
Stéphane Ronsseray ◽  
Monique Lehmann ◽  
Danielle Nouaud ◽  
Dominique Anxolabéhère
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Recombination ◽  
Natural Populations ◽  
P Element ◽  
Single Element ◽  
Heterochromatin Protein 1 ◽  
X Chromosomes ◽  
P Elements ◽  
Associated Sequences ◽  
Regulatory Properties

Abstract Genetic recombination was used in Drosophila melanogaster to isolate P elements, inserted at the telomeres of X chromosomes (cytological site 1A) from natural populations, in a genetic background devoid of other P elements. We show that complete maternally inherited P repression in the germline (P cytotype) can be elicited by only two autonomous P elements at 1A and that a single element at this site has partial regulatory properties. The analysis of the surrounding chromosomal regions of the P elements at 1A shows that in all cases these elements are flanked by Telomeric Associated Sequences, tandemly repetitive noncoding sequences that have properties of heterochromatin. In addition, we show that the regulatory properties of P elements at 1A can be inhibited by some of the mutant alleles of the Su(var)205 gene and by a deficiency of this gene. However, the regulatory properties of reference P strains (Harwich and Texas 007) are not impaired by Su(var)205 mutations. Su(var)205 encodes Heterochromatin Protein 1 (HP1). These results suggest that the HP1 dosage effect on the P element properties is sitedependent and could involve the structure of the chromatin.

scholarly journals Hybrid dysgenesis-induced quantitative variation on the X chromosome of Drosophila melanogaster.

Genetics ◽  
1990 ◽  
Vol 124 (3) ◽  
pp. 627-636
Author(s):  
C Q Lai ◽  
T F Mackay
Keyword(s):  
Drosophila Melanogaster ◽  
X Chromosome ◽  
Quantitative Traits ◽  
Natural Populations ◽  
Quantitative Variation ◽  
Hybrid Dysgenesis ◽  
X Chromosomes ◽  
Bristle Number ◽  
Seven Generations ◽  
Polygenic Variation

Abstract To determine the ability of the P-M hybrid dysgenesis system of Drosophila melanogaster to generate mutations affecting quantitative traits, X chromosome lines were constructed in which replicates of isogenic M and P strain X chromosomes were exposed to a dysgenic cross, a nondysgenic cross, or a control cross, and recovered in common autosomal backgrounds. Mutational heritabilities of abdominal and sternopleural bristle score were in general exceptionally high-of the same magnitude as heritabilities of these traits in natural populations. P strain chromosomes were eight times more mutable than M strain chromosomes, and dysgenic crosses three times more effective than nondysgenic crosses in inducing polygenic variation. However, mutational heritabilities of the bristle traits were appreciable for P strain chromosomes passed through one nondysgenic cross, and for M strain chromosomes backcrossed for seven generations to inbred P strain females, a result consistent with previous observations on mutations affecting quantitative traits arising from nondysgenic crosses. The new variation resulting from one generation of mutagenesis was caused by a few lines with large effects on bristle score, and all mutations reduced bristle number.

scholarly journals Naturally occurring variation in the restriction map of the amy region of Drosophila melanogaster.

Genetics ◽  
1988 ◽  
Vol 119 (3) ◽  
pp. 619-629
Author(s):  
C H Langley ◽  
A E Shrimpton ◽  
T Yamazaki ◽  
N Miyashita ◽  
Y Matsuo ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Restriction Site ◽  
Natural Populations ◽  
Alpha Amylase ◽  
Low Frequencies ◽  
Linkage Disequilibria ◽  
Restriction Sites ◽  
Site Variation ◽  
Transcriptional Units ◽  
Polymorphic Restriction

Abstract The restriction maps of 85 alleles of the Amy region of Drosophila melanogaster from natural populations were surveyed. A subset of these were also scored for allozyme phenotype and adult enzyme activity of alpha-amylase. Large insertions were found in 12% of the alleles in a 15-kb region surrounding the two transcriptional units of the duplicated Amy locus. The low frequencies at which each of these large insertions were found are consistent with earlier reports of variation in other loci. Four small deletions were found in the region 5' to the Amy genes. Each was also rare in the population. Restriction site variation provided an estimate of per nucleotide heterozygosity of 0.006. Several statistically significant linkage disequilibria were observed between four polymorphic restriction sites and the allozymes. Adult alpha-amylase activity was correlated with the allozymes and with the polymorphism at one restriction site close to the transcriptional units.

A Genetically Marked I Element in Drosophila melanogaster Can Be Mobilized When ORF2 Is Provided in trans

Genetics ◽  
1998 ◽  
Vol 148 (1) ◽  
pp. 267-275
Author(s):  
Isabelle Busseau ◽  
Sophie Malinsky ◽  
Maria Balakireva ◽  
Marie-Christine Chaboissier ◽  
Danielle Teninges ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Heat Shock ◽  
Reverse Transcriptase ◽  
Germ Line ◽  
Ltr Retrotransposons ◽  
Low Frequencies ◽  
High Frequencies ◽  
In Trans ◽  
Very High Frequencies ◽  
Very High

Abstract I factors in Drosophila melanogaster are non-LTR retrotransposons similar to mammalian LINEs. They transpose at very high frequencies in the germ line of SF females resulting from crosses between reactive females, devoid of active I factors, and inducer males, containing active I factors. The vermilion marked IviP2 element was designed to allow easy phenotypical screening for retrotransposition events. It is deleted in ORF2 and therefore cannot produce reverse transcriptase. IviP2 can be mobilized at very low frequencies by actively transposing I factors in the germ line of SF females. This paper shows that IviP2 can be mobilized more efficiently in the germ line of strongly reactive females in the absence of active I factors, when it is trans-complemented by the product of ORF2 synthesized from the hsp70 heat-shock promoter. This represents a promising step toward the use of marked I elements to study retrotransposition and as tools for mutagenesis.

scholarly journals Variation in Y Chromosome Segregation in Natural Populations of Drosophila melanogaster

Genetics ◽  
1987 ◽  
Vol 115 (1) ◽  
pp. 143-151
Author(s):  
Andrew G Clark
Keyword(s):  
Drosophila Melanogaster ◽  
Y Chromosome ◽  
Chromosome Segregation ◽  
Significant Variation ◽  
Natural Populations ◽  
Meiotic Drive ◽  
Adult Offspring ◽  
Functional Variation ◽  
Y Chromosomes ◽  
Geographic Origins

ABSTRACT Functional variation among Y chromosomes in natural populations of Drosophila melanogaster was assayed by a segregation study. A total of 36 Y chromosomes was extracted and ten generations of replacement backcrossing yielded stocks with Y chromosomes in two different genetic backgrounds. Eleven of the Y chromosomes were from diverse geographic origins, and the remaining 25 were from locally captured flies. Segregation of sexes in adult offspring was scored for the four possible crosses among the two backgrounds with each Y chromosome. Although the design confounds meiotic drive and effects on viability, statistical partitioning of these effects reveals significant variation among lines in Y chromosome segregation. Results are discussed in regards to models of Y-linked segregation and viability effects, which suggest that Y-linked adaptive polymorphism is unlikely.

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