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.

scholarly journals Early split between African and European populations of Drosophila melanogaster

2018 ◽  
Author(s):  
Adamandia Kapopoulou ◽  
Martin Kapun ◽  
Pavlos Pavlidis ◽  
Bjorn Pieper ◽  
Ricardo Wilches ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Natural Populations ◽  
Divergence Time ◽  
Fruit Fly ◽  
European Population ◽  
Genetic Admixture ◽  
Demographic Models ◽  
African Populations ◽  
Adaptive Processes ◽  
European Populations

AbstractNatural populations of the fruit fly Drosophila melanogaster have been used extensively as a model system to investigate the effect of neutral and selective processes on genetic variation. The species expanded outside its Afrotropical ancestral range during the last glacial period and numerous studies have focused on identifying molecular adaptations associated with the colonization of northern habitats. The sequencing of many genomes from African and non-African natural populations has facilitated the analysis of the interplay between adaptive and demographic processes. However, most of the non-African sequenced material has been sampled from American and Australian populations that have been introduced within the last hundred years following recent human dispersal and are also affected by recent genetic admixture with African populations. Northern European populations, at the contrary, are expected to be older and less affected by complex admixture patterns and are therefore more appropriate to investigate neutral and adaptive processes. Here we present a new dataset consisting of 14 fully sequenced haploid genomes sampled from a natural population in 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. We show that allowing for gene flow between populations in neutral demographic models leads to a significantly better fit to the data and strongly affects estimates of the divergence time and of the size of the bottleneck in the European population. Our results indicate that the time of divergence between cosmopolitan and ancestral populations is 30,000 years older than reported by previous studies.

scholarly journals Female Genotypes Affect Sperm Displacement in Drosophila

Genetics ◽  
1998 ◽  
Vol 149 (3) ◽  
pp. 1487-1493 ◽  
Author(s):  
Andrew G Clark ◽  
David J Begun
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Variation ◽  
Natural Populations ◽  
Isogenic Line ◽  
Female Fitness ◽  
Sperm Displacement ◽  
Extensive Variation ◽  
Polymorphic Genes ◽  
Displacement Parameter ◽  
Competitive Success

Abstract Differential success of sperm is likely to be an important component of fitness. Extensive variation among male genotypes in competitive success of sperm in multiply mated females has been documented for Drosophila melanogaster. However, virtually all previous studies considered the female to be a passive vessel. Nevertheless, under certain conditions female fitness could be determined by her role in mediating use of sperm from multiple males. Here we ask whether females differ among genotypes in their tendency to exhibit last-male precedence. Competition of sperm from two tester male genotypes (bwD and B3-09, a third-chromosome isogenic line from Beltsville, MD) was quantified by doubly mating female lines that had been rendered homozygous for X, second, or third chromosomes isolated from natural populations. The composite sperm displacement parameter, P2′, was highly heterogeneous among lines, whether or not viability effects were compensated, implying the presence of polymorphic genes affecting access of sperm to eggs. Genetic variation of this type is completely neutral in the absence of pleiotropy or interaction between variation in the two sexes.

scholarly journals GENETIC DIFFERENTIATION BETWEEN GEOGRAPHICALLY DISTANT POPULATIONS OF DROSOPHILA MELANOGASTER

Genetics ◽  
1982 ◽  
Vol 101 (2) ◽  
pp. 235-256
Author(s):  
Rama S Singh ◽  
Donal A Hickey ◽  
Jean David
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Differentiation ◽  
Gene Frequency ◽  
Natural Populations ◽  
Allozyme Variation ◽  
Clinal Variation ◽  
Significant Genetic Differentiation ◽  
African Populations ◽  
Latitudinal Clines ◽  
North And South

ABSTRACT We have studied allozyme variation at 26 gene loci in nine populations of Drosophila melanogaster originating on five different continents. The distant populations show significant genetic differentiation. However, only half of the loci studied have contributed to this differentiation; the other half show identical patterns in all populations. The genetic differentiation in North American, European and African populations is correlated with the major climatic differences between north and south. These differences arise mainly from seven loci that show gene-frequency patterns suggestive of latitudinal clines in allele frequencies. The clinal variation is such that subtropical populations are more heterozygous than temperate populations. These results are discussed in relation to the selectionist and neutralist hypotheses of genetic variation in natural populations.

scholarly journals Genetic variation in the dietary sucrose modulation of enzyme activities in Drosophila melanogaster

1984 ◽  
Vol 43 (3) ◽  
pp. 307-321 ◽  
Author(s):  
Billy W. Geer ◽  
Cathy C. Laurie-Ahlberg
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Variation ◽  
Enzyme Activities ◽  
Glycogen Synthesis ◽  
Krebs Cycle ◽  
Natural Populations ◽  
Substitution Lines ◽  
Chromosome Substitution Lines ◽  
High Sucrose Diet ◽  
Selection Of

SUMMARYGenetic variation in the modulating effect of dietary sucrose was assessed in Drosophila melanogaster by examining 27 chromosome substitution lines coisogenic for the X and second chromosomes and possessing different third isogenic chromosomes derived from natural populations. An increase in the concentration of sucrose from 0·1% to 5% in modified Sang's medium C significantly altered the activities of 11 of 15 enzyme activities in third instar larvae, indicating that dietary sucrose modulates many, but not all, of the enzymes of D. melanogaster. A high sucrose diet promoted high activities of enzymes associated with lipid and glycogen synthesis and low activities of enzymes of the glycolytic and Krebs cycle pathways, reflecting the physiological requirements of the animal. Analyses of variance revealed significant genetic variation in the degrees to which sucrose modulated several enzyme activities. Analysis of correlations revealed some relationships between enzymes in the genetic effects on the modulation process. These observations suggest that adaptive evolutionary change may depend in part on the selection of enzyme activity modifiers that are distributed throughout the genome.

scholarly journals Accumulation of P elements in minority inversions in natural populations of Drosophila melanogaster

1992 ◽  
Vol 59 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Walter F. Eanes ◽  
Cedric Wesley ◽  
Brian Charlesworth
Keyword(s):  
Mathematical Model ◽  
Drosophila Melanogaster ◽  
Copy Number ◽  
Natural Populations ◽  
P Element ◽  
P Elements ◽  
Chromosomal Inversions ◽  
Associated Production ◽  
African Populations ◽  
Parameter Values

SummaryThe accumulation of a transposable element inside chromosomal inversions is examined theoretically by a mathematical model, and empirically by counts of P elements associated with inversion polymorphisms in natural populations of Drosophila melanogaster. The model demonstrates that, if heterozygosity for an inversion effectively reduces element associated production of detrimental chromosome rearrangements, a differential accumulation of elements is expected, with increased copy number inside the minority inversion. Several-fold differential accumulations are possible with certain parameter values. We present data on P element counts for inversion polymorphisms on all five chromosome arms of 157 haploid genomes from two African populations. Our observations show significantly increased numbers of elements within the regions associated with the least common, or minority arrangements, in natural inversion polymorphisms.

scholarly journals Quantitative genetic variation of enzyme activities in natural populations of Drosophila melanogaster

1980 ◽  
Vol 77 (2) ◽  
pp. 1073-1077 ◽  
Author(s):  
C. C. Laurie-Ahlberg ◽  
G. Maroni ◽  
G. C. Bewley ◽  
J. C. Lucchesi ◽  
B. S. Weir
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Variation ◽  
Enzyme Activities ◽  
Natural Populations ◽  
Quantitative Genetic

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.

A cline and other patterns of genetic variation in Cochliobolus carbonum isolates pathogenic to corn in North Carolina

1984 ◽  
Vol 62 (5) ◽  
pp. 995-1005 ◽  
Author(s):  
Deborah J. Lodge ◽  
Kurt J. Leonard
Keyword(s):  
North Carolina ◽  
Genetic Variation ◽  
Gene Flow ◽  
Cultural Practices ◽  
Natural Populations ◽  
Cochliobolus Carbonum ◽  
Historical Factors ◽  
Race 2 ◽  
Eastern North Carolina ◽  
High Elevations

Patterns of genetic variation were studied in natural populations of Cochliobolus carbonum Nelson (anamorph Helminthosporium carbonum Ullstrup), a haploid asexually reproducing fungus. Two virulence races (2 and 3) are common on corn in North Carolina. Race 3 has occurred in the Appalachian mountains for at least 25 years, but has recently expanded its range eastward. The expanded range of race 3 cannot be explained by adaptation through parasexual recombination between races or mutation alone. Five polymorphic traits in addition to virulence were compared in races 2 and 3 to evaluate possible recombination between races. If sexual recombination occurred between races, it was rare and was not detected in this study. The simplest explanation for the expansion of race 3 involves historical factors such as increased corn production and changes in weather which aided gene flow. A steep cline was found on the Appalachian escarpment, where the proportion of race 3 isolates dropped from 100% at high elevations to 30% at low elevations over a distance of 7–20 km. No barriers to gene flow were found on the escarpment, suggesting that the environment and possibly cultural practices may restrict race 3 at low elevations and race 2 at high elevations. Race 3 may adapt to conditions in eastern North Carolina only slowly via mutation unless recombination occurs and has gone undetected.

Sign in / Sign up

Export Citation Format

Share Document