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 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.

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.

Electrophoretic variability in natural populations of Drosophila melanogaster and Drosophila simulans

Genetica ◽  
1982 ◽  
Vol 59 (3) ◽  
pp. 191-201 ◽  
Author(s):  
V. M. Cabrera ◽  
A. M. Gonz�lez ◽  
J. M. Larruga ◽  
A. Gull�n
Keyword(s):  
Drosophila Melanogaster ◽  
Natural Populations ◽  
Drosophila Simulans

scholarly journals The relationship between the rate of transposition and transposable element copy number for copia and Doc retrotransposons of Drosophila melanogaster

1998 ◽  
Vol 72 (1) ◽  
pp. 1-11 ◽  
Author(s):  
ELENA G. PASYUKOVA ◽  
SERGEY V. NUZHDIN ◽  
DMITRY A. FILATOV
Keyword(s):  
Drosophila Melanogaster ◽  
Copy Number ◽  
Self Regulation ◽  
Natural Populations ◽  
Strong Positive Correlation ◽  
Positive Correlation ◽  
Transposition Rate ◽  
Copy Numbers ◽  
Starting Point ◽  
The Relationship

We present data on the relationship between the rate of transposition and copy number in the genome for the copia and Doc retrotransposons of Drosophila melanogaster. copia and Doc transposition rates were directly measured in sublines of the isogenic 2b line using individual males or females, respectively, with a range of copia copy numbers from 49 to 103 and Doc copy numbers from 112 to 235 per genome. Transposition rates varied from 3×10−4 to 2×10−2 for copia and from 2×10−4 to 2×10−3 for Doc. A positive relationship between transposition rate and copy number was found both for copia and for Doc when the data were analysed across all the 2b individuals; no significant correlation was found when the data were analysed across the subline means for both retrotransposons tested. Overall, correlation between copia and Doc transposition rate and their copy number in the genome, if any, was not negative, which would be expected if transposable elements (TEs) self-regulate their copy number. Thus, for copia and Doc no evidence for self-regulation was provided, and at least for these two TEs this hypothesis is not favoured for explaining the maintenance of the stable copy number that is characteristic for natural populations. The transposition rate of copia was measured twice, and a strong positive correlation between copy number and transposition rate both across individuals and subline means was found in 1994, while in 1995 no correlation was found. This fact is in agreement with the hypothesis that a positive correlation between the rate of transposition and TE copy number may be a default starting point for future host–TE coevolution.

scholarly journals Abundant genetic variability in Drosophila simulans for hybrid female lethality in interspecific crosses to Drosophila melanogaster

2012 ◽  
Vol 94 (1) ◽  
pp. 1-7 ◽  
Author(s):  
PIERRE R. GÉRARD ◽  
DAVEN C. PRESGRAVES
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Variability ◽  
Maternal Effect ◽  
Hybrid Sterility ◽  
Natural Populations ◽  
Drosophila Simulans ◽  
Interspecific Crosses ◽  
Hybrid Lethality ◽  
Hybrid Female ◽  
Multiple Loci

SummaryIntrinsic postzygotic reproductive isolation is thought to result from the substitution of multiple harmless or beneficial genetic differences between species that are incidentally deleterious when combined in species hybrids, causing hybrid sterility or inviability. Genetic variability for hybrid sterility or inviability phenotypes is, however, rarely assessed in natural populations. Here, we assess variation for Drosophila simulans-encoded maternal factor(s) that cause lethality in D. simulans–Drosophila melanogaster F1 hybrid females. First, we survey genetic variability in the strength of D. simulans-mediated maternal effect hybrid lethality among 37 geographic and laboratory isolates. We find abundant variability in the strength of maternal effect hybrid lethality, ranging from complete lethality to none. Second, we assess maternal effect hybrid lethality for a subset of wild isolates made heterozygous with two so-called hybrid rescue strains. The results suggest that the D. simulans maternal effect hybrid lethality involves a diversity of alleles and/or multiple loci.

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