A Comprehensive Study of Genic Variation in Natural Populations of Drosophila melanogaster. I. Estimates of Gene Flow from Rare Alleles

Genetics ◽  
1987 ◽  
Vol 115 (2) ◽  
pp. 313-322
Author(s):  
Rama S Singh ◽  
Lorenz R Rhomberg
Keyword(s):  
Drosophila Melanogaster ◽  
Gene Flow ◽  
West Coast ◽  
Natural Populations ◽  
Evolutionary Significance ◽  
Study Program ◽  
Asian Populations ◽  
Rare Alleles ◽  
Geographic Populations ◽  
Genic Variation

ABSTRACT In order to assess the evolutionary significance of molecular variation in natural populations of Drosophila melanogaster, we have started a comprehensive genetic variation study program employing a relatively large number of gene-protein loci and an array of populations obtained from various geographic locations throughout the world. In this first report we provide estimates of gene flow based on the spatial distributions of rare alleles at 117 gene loci in 15 worldwide populations of D. melanogaster . Estimates of Nm (number of migrants exchanged per generation among populations) range from 1.09 in East-Asian populations (Taiwan, Vietnam and Australia) to 2.66 in West-Coast populations of North America. These estimates, among geographic populations separated by hundreds or even thousands of miles, suggest that gene flow among neighboring populations of D. melanogaster is quite extensive. This means that, for selectively neutral genes, we should expect little differentiation among neighboring populations. A survey of eight West-Coast populations of D. melanogaster (geographically comparable to Drosophila pseudoobscura) showed that in spite of extensive gene flow, populations of D. melanogaster show much more geographic differentiation than comparable populations of D. pseudoobscura. From this we conclude that migration in combination with natural selection rather than migration alone is responsible for the geographic uniformity of molecular polymorphisms in D. pseudoobscura.

scholarly journals Molecular Evolution of Duplicated Amylase Gene Regions in Drosophila melanogaster: Evidence of Positive Selection in the Coding Regions and Selective Constraints in the cis-Regulatory Regions

Genetics ◽  
2001 ◽  
Vol 157 (2) ◽  
pp. 667-677
Author(s):  
Hitoshi Araki ◽  
Nobuyuki Inomata ◽  
Tsuneyuki Yamazaki
Keyword(s):  
Drosophila Melanogaster ◽  
Molecular Evolution ◽  
Positive Selection ◽  
Natural Populations ◽  
Sliding Window ◽  
Selective Constraint ◽  
Proximal Region ◽  
Coding Regions ◽  
Asian Populations ◽  
Flanking Region

Abstract In this study, we randomly sampled Drosophila melanogaster from Japanese and Kenyan natural populations. We sequenced duplicated (proximal and distal) Amy gene regions to test whether the patterns of polymorphism were consistent with neutral molecular evolution. Fst between the two geographically distant populations, estimated from Amy gene regions, was 0.084, smaller than reported values for other loci, comparing African and Asian populations. Furthermore, little genetic differentiation was found at a microsatellite locus (DROYANETSB) in these samples (Gst′=−0.018). The results of several tests (Tajima's, Fu and Li's, and Wall's tests) were not significantly different from neutrality. However, a significantly higher level of fixed replacement substitutions was detected by a modified McDonald and Kreitman test for both populations. This indicates that positive selection occurred during or immediately after the speciation of D. melanogaster. Sliding-window analysis showed that the proximal region 1, a part of the proximal 5′ flanking region, was conserved between D. melanogaster and its sibling species, D. simulans. An HKA test was significant when the proximal region 1 was compared with the 5′ flanking region of Alcohol dehydrogenase (Adh), indicating a severe selective constraint on the Amy proximal region 1. These results suggest that natural selection has played an important role in the molecular evolution of Amy gene regions in D. melanogaster.

Estimates of gene flow from rare alleles in natural populations of medfly Ceratitis capitata (Diptera: Tephritidae)

2004 ◽  
Vol 94 (5) ◽  
pp. 449-456 ◽  
Author(s):  
A. Kourti
Keyword(s):  
Gene Flow ◽  
Ceratitis Capitata ◽  
Natural Populations ◽  
Clinal Variation ◽  
African Populations ◽  
The World ◽  
Rare Alleles ◽  
Geographical Populations ◽  
Latitudinal Clines ◽  
North And South

AbstractGene flow based on the spatial distribution of rare alleles at 25 gene loci was estimated in 15 populations of Ceratitis capitata (Wiedemann) from different parts of the world. Estimates of Nm, the number of migrants exchanged per generation among populations in different regions of the world, appeared to be quite similar, ranging from 3.36 in tropical Africa to 2.94 in the New World and 2.72 in Mediterranean basin populations. This suggests that gene flow among neighbouring populations of medfly is quite extensive. The genetic differentiation in American, Mediterranean and African populations was related to major climatic differences between North and South. These differences arise mainly from five loci that showed gene frequency patterns suggestive of latitudinal clines in allele frequencies. The clinal variation was such that tropical-subtropical populations were more heterozygous than temperate populations. It was concluded that gene flow, counteracting the forces of natural selection and genetic drift, determines the extent to which geographical populations of C. capitata are differentiated.

scholarly journals copia expression is variable among natural populations of Drosophila.

Genetics ◽  
1990 ◽  
Vol 126 (2) ◽  
pp. 375-385
Author(s):  
A K Csink ◽  
J F McDonald
Keyword(s):  
Drosophila Melanogaster ◽  
Copy Number ◽  
Natural Populations ◽  
Drosophila Simulans ◽  
Evolutionary Significance ◽  
Diverse Populations ◽  
Copy Number Analysis ◽  
Transcript Levels ◽  
Phylogenetic Pattern ◽  
Drosophila Mauritiana

Abstract A survey of copia (retroviral-like element) expression in flies representing 37 populations worldwide of Drosophila melanogaster, Drosophila simulans and Drosophila mauritiana demonstrates that, although copia elements are present in all three species, copia-encoded transcripts are detectable only in D. melanogaster. Levels of copia transcripts vary nearly 100-fold among flies representing geographically diverse populations of D. melanogaster and this variation is not correlated with variability in copia copy number. Analysis of transcript levels in interpopulation hybrids demonstrates that much of this variability may be attributable to the action of trans-acting controls. The geographic and phylogenetic pattern of copia expression suggests that moderate to high levels of copia expression may be a relatively recent evolutionary acquisition. The potential evolutionary significance of these findings is discussed.

scholarly journals GENE FLOW IN NATURAL POPULATIONS OF DROSOPHILA MELANOGASTER WITH SPECIAL REFERENCE TO LETHAL ALLELISM RATES AND PROTEIN VARIATION

Genetics ◽  
1986 ◽  
Vol 113 (1) ◽  
pp. 73-89
Author(s):  
Tsuneyuki Yamazaki ◽  
Jong-Kil Choo ◽  
Takao K Watanabe ◽  
Naoyuki Takahata
Keyword(s):  
Drosophila Melanogaster ◽  
Gene Flow ◽  
Far East ◽  
Geographic Distance ◽  
Natural Populations ◽  
The Far East ◽  
Cage Population ◽  
Lethal Allelism ◽  
Two Populations ◽  
Very High

ABSTRACT A simultaneous survey of 14 protein loci, together with frequencies and within- and between-population allelism rates of lethal chromosomes, was carried out in five (four Japanese and one Korean) natural populations and one cage population of Drosophila melanogaster. It was found that lethal allelism rates decrease rapidly as geographic distance between two populations increases, while variation at protein loci shows a remarkable similarity over all populations examined. These findings suggest that there are very high levels of gene flow in these natural populations and that selection at protein loci which can maintain substantial geographic variation, if present, is overshadowed by gene flow. There is no indication that invasion of D. melanogaster to the Far East occurred so recently that the frequencies of lethal chromosomes are still in nonequilibrium.

A Comprehensive Study of Genic Variation in Natural Populations of Drosophila melanogaster. III. Variations in Genetic Structure and Their Causes Between Drosophila melanogaster and Its Sibling Species Drosophila simulans

Genetics ◽  
1987 ◽  
Vol 117 (4) ◽  
pp. 697-710
Author(s):  
M Choudhary ◽  
Rama S Singh
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Structure ◽  
Natural Populations ◽  
Drosophila Simulans ◽  
Geographic Differentiation ◽  
Dna Variation ◽  
Genic Variation ◽  
Pattern Of Variation ◽  
Physiological Characters ◽  
Comprehensive Study

ABSTRACT The natural populations of Drosophila melanogaster and Drosophila simulans were compared for their genetic structure. A total of 114 gene-protein loci were studied in four mainland (from Europe and Africa) and an island (Seychelle) populations of D. simulans and the results were compared with those obtained on the same set of homologous loci in fifteen worldwide populations of D. melanogaster. The main results are as follows: (1) D. melanogaster shows a significantly higher proportion of loci polymorphic than D. simulans (52% vs. 39%, P < 0.05), (2) both species have similar mean heterozygosity and mean number of alleles per locus, (3) the two species share some highly polymorphic loci but they do not share loci that show high geographic differentiation, and (4) D. simulans shows significantly less geographic differentiation than D. melanogaster. The differences in genetic differentiation between the two species are limited to loci located on the X and second chromosomes only; loci on the third chromosome show similar level of geographic differentiation in both species. These two species have previously been shown to differ in their pattern of variation for chromosomal polymorphisms, quantitative and physiological characters, two-dimensional electrophoretic (2DE) proteins, middle repetitive DNA and mitochondrial DNA. Variation in niche-widths and/or genetic "strategies" of adaptation appear to be the main causes of differences in the genetic structure of these two species.

scholarly journals GENETIC HETEROGENEITY WITHIN ELECTROPHORETIC "ALLELES" OF XANTHINE DEHYDROGENASE IN DROSOPHILA PSEUDOOBSCURA

Genetics ◽  
1976 ◽  
Vol 84 (3) ◽  
pp. 609-629
Author(s):  
R S Singh ◽  
R C Lewontin ◽  
A A Felton
Keyword(s):  
Allelic Variation ◽  
Natural Populations ◽  
Heat Stability ◽  
Xanthine Dehydrogenase ◽  
Isolated Population ◽  
Population Differences ◽  
Average Heterozygosity ◽  
Geographic Populations ◽  
Genic Variation

ABSTRACT An experimental plan for an exhaustive determination of genic variation at structural gene loci is presented. In the initial steps of this program, 146 isochromosomal lines from 12 geographic populations of D. pseudoobscura were examined for allelic variation of xanthine dehydrogenase by the serial use of 4 different electrophoretic conditions and a heat stability test. The 5 criteria revealed a total of 37 allelic classes out of the 146 genomes examined where only 6 had been previously revealed by the usual method of gel electrophoresis. This immense increase in genic variation also showed previously unsuspected population differences between the main part of the species distribution and the isolated population of Bogotá, Colombia, in conformity with the known partial reproductive isolation of the Bogotá population. The average heterozygosity at the Xdh locus is at least 72% in natural populations. This result, together with the very large number of alleles segregating and the pattern of allelic frequencies, has implications for theories of genetic polymorphism which are discussed.

scholarly journals A comprehensive study of genic variation in natural populations of Drosophila melanogaster. VI. Patterns and processes of genic divergence between D. melanogaster and its sibling species, Drosophila simulans.

Genetics ◽  
1992 ◽  
Vol 130 (4) ◽  
pp. 843-853
Author(s):  
M Choudhary ◽  
M B Coulthart ◽  
R S Singh
Keyword(s):  
Drosophila Melanogaster ◽  
Sibling Species ◽  
Natural Populations ◽  
Drosophila Simulans ◽  
Significant Heterogeneity ◽  
Homologous Proteins ◽  
Two Dimensional Gel Electrophoresis ◽  
Protein Coding ◽  
Genic Variation ◽  
Patterns And Processes

Abstract We present here an extensive set of data on allelic differences between homologous proteins of Drosophila melanogaster and its sibling species, Drosophila simulans, obtained by nondenaturing one-dimensional, and denaturing two-dimensional gel electrophoresis. The data suggest that, for these two species, (1) approximately 10% of protein-coding loci have no alleles in common in our sample, (2) the extent of genic variation at a locus (mean heterozygosity) within a species is not correlated with the extent of divergence (Nei's genetic distance) at that locus between species, and (3) significant heterogeneity of divergence rates exists for different structural/functional classes of loci. These results are discussed in the context of the dynamics of genetic variation within and between species.

scholarly journals Demographic analyses of a new sample of haploid genomes from a Swedish population of Drosophila melanogaster

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Adamandia Kapopoulou ◽  
Martin Kapun ◽  
Bjorn Pieper ◽  
Pavlos Pavlidis ◽  
Ricardo Wilches ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Variation ◽  
Gene Flow ◽  
Natural Populations ◽  
Swedish Population ◽  
Demographic Models ◽  
African Populations ◽  
Variation Data ◽  
Adaptive Processes ◽  
Northern Species

AbstractEuropean and African natural populations of Drosophila melanogaster have been the focus of several studies aiming at inferring demographic and adaptive processes based on genetic variation data. However, in these analyses little attention has been given to gene flow between African and European samples. Here we present a dataset consisting of 14 fully sequenced haploid genomes sampled from a natural population from the northern species range (Umeå, Sweden). We co-analyzed this new data with an African population to compare the likelihood of several competing demographic scenarios for European and African populations and show that gene flow improves the fit of demographic models to data.

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