Research Topics
Genomes and Genes | W StephanSummaryAffiliation: University of Maryland Country: USA Publications
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Publications
Perturbation analysis of a two-locus model with directional selection and recombinationW Stephan
Department of Zoology, University of Maryland, College Park 20742, USA
J Math Biol 34:95-109. 1995..It is demonstrated that the zeroth-order solution of this two-scale approach approximates the numerical solution of the model well, even if recombination rate is on the order of the selection coefficients...
The rate of compensatory evolutionW Stephan
Department of Zoology, University of Maryland, College Park 20742 4415, USA
Genetics 144:419-26. 1996..We discuss the dynamics of evolutionary substitutions of compensatory mutants in relation of WRIGHT's shifting balance theory of evolution and use our results to analyze the substitution process in helices of mRNA secondary structures...
Site-directed mutations reveal long-range compensatory interactions in the Adh gene of Drosophila melanogasterJ Parsch
Department of Zoology, University of Maryland, College Park 20742, USA
Proc Natl Acad Sci U S A 94:928-33. 1997..However, our results do not fit the classical compensatory substitution model because the second mutation by itself (in the 3' UTR) did not show a measurable reduction in gene expression...
A highly conserved sequence in the 3'-untranslated region of the drosophila Adh gene plays a functional role in Adh expressionJ Parsch
Molecular and Cell Biology Program, University of Maryland, College Park, Maryland 20742, USA
Genetics 151:667-74. 1999..The selective difference between these two sequence changes, which have similar effects on ADH activity, may be explained by different metabolic costs associated with the increase in activity...
Analysis of a genetic hitchhiking model, and its application to DNA polymorphism data from Drosophila melanogasterT H Wiehe
Department of Zoology, University of Maryland, College Park 20742
Mol Biol Evol 10:842-54. 1993..3 x 10(-8). Additional data are needed to estimate this parameter more precisely. The estimation of alpha v is important, as this parameter determines the shape of the frequency distribution of strongly selected substitutions...
Multi-locus selection and the structure of variation at the white gene of Drosophila melanogasterD A Kirby
Department of Zoology, University of Maryland, College Park 20742, USA
Genetics 144:635-45. 1996..A multi-locus selection model that combines features from both hypotheses and takes the recent history of D. melanogaster into account may be the best explanation for these data...
Molecular evolution of the metallothionein gene Mtn in the melanogaster species group: results from Drosophila ananassaeW Stephan
Department of Zoology, University of Maryland, College Park 20742
Genetics 138:135-43. 1994..pseudoobscura Mtn allele, suggesting that the short intron is the ancestral form and that the transition from the short to the long intron occurred within the melanogaster species group.(ABSTRACT TRUNCATED AT 250 WORDS)..
A test of the background selection hypothesis based on nucleotide data from Drosophila ananassaeW Stephan
Department of Zoology, University of Maryland, College Park, MD 20742, USA
Proc Natl Acad Sci U S A 95:5649-54. 1998..Instead, it may have been caused by a recent hitchhiking event that was limited to the northern species range...
Haplotype test reveals departure from neutrality in a segment of the white gene of Drosophila melanogasterD A Kirby
Department of Zoology, University of Maryland, College Park 20742, USA
Genetics 141:1483-90. 1995..We proposed that these unusually large haplotype blocks are due to positive selection on polymorphisms within the white gene, including a replacement polymorphism, Arg-->Leu, within this segment...
RNA folding in Drosophila shows a distance effect for compensatory fitness interactionsW Stephan
Department of Zoology, University of Maryland, College Park 20742
Genetics 135:97-103. 1993..However, the rate of joint fixation drops as distance between sites increases and recombination breaks up favorable combinations. RNA secondary structure was also used to interpret patterns of linkage disequilibrium at Adh...
Long-range base pairing in Drosophila and human mRNA sequencesJ Parsch
Molecular and Cell Biology Program, University of Maryland, College Park, USA
Mol Biol Evol 15:820-6. 1998..The human pairings appear to be stronger and localized to more specific regions near the ends of the mRNA sequence than those of Drosophila...
Maintenance of pre-mRNA secondary structure by epistatic selectionD A Kirby
Department of Zoology, University of Maryland, College Park 20742, USA
Proc Natl Acad Sci U S A 92:9047-51. 1995....
Reduced levels of DNA polymorphism and fixed between-population differences in the centromeric region of Drosophila ananassaeW Stephan
Department of Zoology, University of Maryland, College Park 20742
Genetics 132:1039-45. 1992..The data indicate that different selective sweeps have occurred in the two populations. The possible role of genetic hitchhiking in rapid population differentiation in gene regions of restricted recombination is discussed...
