Molecular genetic variation in the centromeric region of the X chromosome in three Drosophila ananassae populations. I. Contrasts between the vermilion and forked loci.

Abstract We have surveyed three natural populations of Drosophila ananassae for restriction map variation at the forked (f) and vermilion (v) loci, using 6-cutter restriction enzymes. Both loci are located in the centromeric region of the X chromosome. Two major conclusions can be drawn from the data. First, we found strong evidence for population subdivision, i.e., significant differences in the frequency distributions of polymorphisms and/or haplotypes between the Burma, India, and Brazil populations. Secondly, the pattern of DNA sequence variation between the two loci is unexpectedly different. The level of nucleotide variation in the v locus region is reduced (relative to f), especially in the Burma population. Furthermore, in contrast to v, we found no insertions/deletions larger than 700 bp and no significant linkage disequilibrium at f. The genetic differentiation among subpopulations can readily be attributed to restricted migration as the predominant evolutionary force. According to population genetics theory, the differences in DNA polymorphisms between the two loci are in qualitative agreement with the hypothesis that recombination is reduced in the v locus region ("centromere effect") but not at f. In order to test this hypothesis directly, we determined the cytogenetic positions of several loci in the centromeric region by in situ hybridization and found by comparison with the genetic map that recombination at v is indeed very low, much lower than at f.

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Intraspecific and interspecific variation at the y-ac-sc region of Drosophila simulans and Drosophila melanogaster.

Genetics ◽

10.1093/genetics/130.4.805 ◽

1992 ◽

Vol 130 (4) ◽

pp. 805-816 ◽

Cited By ~ 2

Author(s):

J M Martín-Campos ◽

J M Comerón ◽

N Miyashita ◽

M Aguadé

Keyword(s):

Drosophila Melanogaster ◽

X Chromosome ◽

Length Polymorphism ◽

Restriction Site ◽

Natural Populations ◽

Restriction Enzymes ◽

Drosophila Simulans ◽

Population Subdivision ◽

Telomeric Region ◽

Length Variation

Abstract A 2.2-kb region including the ac gene of Drosophila simulans has been sequenced. Interspecific divergence between Drosophila melanogaster and D. simulans was estimated as 0.0695 and 0.0558 for silent and for all sites, respectively. Estimated silent site divergence for the ac region is comparable to that estimated for other regions of the genome between these species, indicating that silent sites of the ac region are not under significantly stronger functional constraint. Intraspecific variation in both species was also investigated. Restriction-site and length polymorphism in the ac region of D. simulans has been investigated for 103 X chromosome lines sampled from three natural populations in Spain using eight four-cutter restriction enzymes. Neither restriction-site nor length variation was detected in the three populations surveyed. In D. melanogaster restriction-site and length polymorphism in all major transcription units of the y-ac-sc region (23.1-kb region) has been studied using four four-cutter restriction enzymes for 245 X chromosome lines sampled from 10 natural populations (seven from Europe, two from North America and one from Japan). Fourteen restriction-site and 28 length polymorphisms were detected. There was some indication of population subdivision for North American vs. European samples of D. melanogaster. The frequency spectrum of restriction-site polymorphisms in European populations was skewed toward rarer frequencies than predicted by the neutral theory. Comparison of silent site variation at this telomeric region with that in the Adh 5'-flanking region showed a reduced level of heterozygosity in the y-ac-sc region. Since interspecific silent divergence is not reduced in the y-ac-sc region as compared to other regions, the reduction in standing levels of variation at this telomeric locus in both D. simulans and D. melanogaster is most easily explained by a hitchhiking effect of linked selected substitutions.

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Molecular genetic variation in the centromeric region of the X chromosome in three Drosophila ananassae populations. II. The Om(1D) locus.

Molecular Biology and Evolution ◽

10.1093/oxfordjournals.molbev.a040580 ◽

1989 ◽

Keyword(s):

Genetic Variation ◽

X Chromosome ◽

Centromeric Region ◽

Molecular Genetic ◽

Drosophila Ananassae ◽

Molecular Genetic Variation

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Variation in natural populations of Drosophila as revealed by four-cutter analysis

Genome ◽

10.1139/g89-138 ◽

1989 ◽

Vol 31 (2) ◽

pp. 784-787 ◽

Cited By ~ 1

Author(s):

Montserrat Aguadé

Keyword(s):

Restriction Site ◽

Natural Populations ◽

Restriction Enzymes ◽

Dna Polymorphisms ◽

Enzyme Analysis ◽

Restriction Enzyme Analysis ◽

Molecular Variation ◽

Deletion Polymorphism ◽

Isolated Populations ◽

Chromosome Arrangements

Four-cutter restriction enzyme analysis, a recently developed electroblotting technique, enables the survey of restriction site and insertion–deletion polymorphism in natural populations at a fine level of resolution. Using this technique, the distribution of polymorphism among geographically isolated populations of Drosophila melanogaster and in different structural–functional domains of the genome has been studied. A summary of these results is presented and discussed. Recent investigations of molecular variation within and between different chromosome arrangements in Drosophila are presented. Levels of variation in different regions of the X chromosome of D. melanogaster are also discussed.Key words: populations, DNA polymorphisms, Drosophila, restriction enzymes.

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Population Subdivision and Molecular Sequence Variation: Theory and Analysis of Drosophila ananassae Data

Genetics ◽

10.1093/genetics/165.3.1385 ◽

2003 ◽

Vol 165 (3) ◽

pp. 1385-1395

Author(s):

Claus Vogl ◽

Aparup Das ◽

Mark Beaumont ◽

Sujata Mohanty ◽

Wolfgang Stephan

Keyword(s):

Sequence Data ◽

Isolation By Distance ◽

Allele Frequencies ◽

Drosophila Ananassae ◽

Population Subdivision ◽

Variation Theory ◽

Peripheral Populations ◽

Molecular Variation ◽

Data Set ◽

Evolutionary Forces

Abstract Population subdivision complicates analysis of molecular variation. Even if neutrality is assumed, three evolutionary forces need to be considered: migration, mutation, and drift. Simplification can be achieved by assuming that the process of migration among and drift within subpopulations is occurring fast compared to mutation and drift in the entire population. This allows a two-step approach in the analysis: (i) analysis of population subdivision and (ii) analysis of molecular variation in the migrant pool. We model population subdivision using an infinite island model, where we allow the migration/drift parameter 0398; to vary among populations. Thus, central and peripheral populations can be differentiated. For inference of 0398;, we use a coalescence approach, implemented via a Markov chain Monte Carlo (MCMC) integration method that allows estimation of allele frequencies in the migrant pool. The second step of this approach (analysis of molecular variation in the migrant pool) uses the estimated allele frequencies in the migrant pool for the study of molecular variation. We apply this method to a Drosophila ananassae sequence data set. We find little indication of isolation by distance, but large differences in the migration parameter among populations. The population as a whole seems to be expanding. A population from Bogor (Java, Indonesia) shows the highest variation and seems closest to the species center.

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

Genetics ◽

10.1093/genetics/124.3.627 ◽

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.

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Parallelism between male mating propensity and chromosome arrangement frequency in natural populations of Drosophila ananassae

Heredity ◽

10.1038/hdy.1988.42 ◽

1988 ◽

Vol 60 (2) ◽

pp. 269-272 ◽

Cited By ~ 11

Author(s):

B N Singh ◽

Sujata Chatterjee

Keyword(s):

Natural Populations ◽

Drosophila Ananassae ◽

Male Mating ◽

Chromosome Arrangement ◽

Mating Propensity

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Chromosome polymorphism in natural populations of Anopheles quadrimaculatus Say species A and B

Genome ◽

10.1139/g88-024 ◽

1988 ◽

Vol 30 (2) ◽

pp. 138-146 ◽

Cited By ~ 1

Author(s):

P. E. Kaiser ◽

J. A. Seawright ◽

B. K. Birky

Keyword(s):

X Chromosome ◽

Southeastern United States ◽

Polytene Chromosomes ◽

Natural Populations ◽

Chromosome 3 ◽

Chromosome Polymorphism ◽

Chromosome 2 ◽

Anopheles Quadrimaculatus ◽

The Right ◽

Maculipennis Complex

Ovarian polytene chromosomes from eight populations of Anopheles quadrimaculatus in the southeastern United States were observed for chromosomal polymorphisms. Two sibling species, species A and B, each with intraspecific inversions, were distinguished. Species A correlates with the previously published standard maps for salivary gland and ovarian nurse-cell polytene chromosomes. Species A was found at all eight collection sites, and five of these populations also contained species B. Three inversions on the right arm of chromosome 3 were observed in species A. Species B contained a fixed inversion on the X chromosome, one fixed and one floating inversion on the left arm of chromosome 2, and one fixed and one floating inversion on the right arm of chromosome 3. The fixed inversion on the X chromosome makes this the best diagnostic chromosome for distinguishing species A and B. An unusual dimorphism in the left arm of chromosome 3, found in both species A and B, contained two inversions. The heterokaryotypes, as well as two distinct homokaryotypes, were seen in all of the field populations. Intraspecific clinal variations in the frequencies of the species A inversions were noted. The Florida populations were practically devoid of inversions, the Georgia and Alabama populations contained some inversions, and the Arkansas population was mostly homozygous for two of the inversions. The phylogenetic relationships of species A and B to the Maculipennis complex (Nearctic) are discussed.Key words: Anopheles, inversion, populations, chromosome polymorphism, phylogenetics.

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Studies of esterase 6 in Drosophila melanogaster: XIV. Variation of esterase 6 levels controlled by unlinked genes in natural populations

Genetics Research ◽

10.1017/s0016672300025891 ◽

1984 ◽

Vol 43 (2) ◽

pp. 181-190 ◽

Cited By ~ 7

Author(s):

Craig S. Tepper ◽

Anne L. Terry ◽

James E. Holmes ◽

Rollin C. Richmond

Keyword(s):

Drosophila Melanogaster ◽

Structural Gene ◽

X Chromosome ◽

Genetic Background ◽

Natural Populations ◽

Regulatory Elements ◽

Regulatory Locus ◽

The Third ◽

Esterase 6 ◽

Activity Modifiers

SUMMARYThe esterase 6 (Est-6) locus in Drosophila melanogaster is located on the third chromosome and is the structural gene for a carboxylesterase (E.C.3.1.1.1) and is polymorphic for two major electromorphs (slow and fast). Isogenic lines containing X chromosomes extracted from natural populations and substituted into a common genetic background were used to detect unlinked factors that affect the activity of the Est-6 locus. Twofold activity differences of esterase 6 (EST 6) were found among males from these derived lines, which differ only in their X chromosome. These unlinked activity modifiers identify possible regulatory elements. Immunoelectrophoresis was used to estimate quantitatively the levels of specific cross-reacting material in the derived lines. The results show that the variation in activity is due to differences in the amount of EST 6 present. The data are consistent with the hypothesis that there is at least one locus on the X chromosome that regulates the synthesis of EST 6 and that this regulatory locus may be polymorphic in natural populations.

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Growth of four species of juvenile fish associated with the Seagrass Zostera capricorni, in Botany Bay, NSW

Marine and Freshwater Research ◽

10.1071/mf9921189 ◽

1992 ◽

Vol 43 (5) ◽

pp. 1189 ◽

Cited By ~ 12

Author(s):

DG Worthington ◽

DJ Ferrell ◽

SE NcNeill ◽

JD Bell

Keyword(s):

Sea Water ◽

New South ◽

Juvenile Fish ◽

Natural Populations ◽

Length Frequency ◽

Frequency Distributions ◽

South Wales ◽

Time Period ◽

Flow Through ◽

Sampling Programme

Populations of four species of juvenile fish- Rhabdosargus sarba, Acanthopagrus australis, Achoerodus viridis and Girella tricuspidata-were sampled from a seagrass bed in Botany Bay, New South Wales. Fish were collected eight times between 22 March 1990 and 22 February 1991, using a small seine-net. Growth rates were calculated from the progression of cohorts in length-frequency distributions. Cohorts of R. sarba, A. australis and A. viridis grew most slowly during winter (0.02, 0.04 and 0.21 mm day-1, respectively); growth then increased, peaking just prior to the loss of the cohort from the habitat (0.3 1, 0.24 and 0.39 mm day-1). Populations of R. sarba, A. australis and A. viridis were comprised of one or two cohorts that remained in the habitat for at least 3-4 months. Conversely, up to seven cohorts of G. tricuspidata were found between October and February, and most cohorts did not remain in the habitat for more than 2 months. As a result, there were only two confident estimates of growth for G. tricuspidata: 0.23 mm day-1 between October and November, and 0.34 mm day-1 between January and February. Individuals of each species were also kept in a flow-through 4000-L tank of sea water. Growth of cohorts of fish kept in the tank was very similar to that found in natural populations during the same time period. The rates of recruitment and loss of cohorts from seagrass can be rapid and these factors must be considered in designing a sampling programme to assess growth by analysis of length-frequency distributions.

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