S W Schaeffer

Summary

Affiliation: Pennsylvania State University
Country: USA

Publications

  1. pmc Polytene chromosomal maps of 11 Drosophila species: the order of genomic scaffolds inferred from genetic and physical maps
    Stephen W Schaeffer
    Department of Biology and Institute of Molecular Evolutionary Genetics, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
    Genetics 179:1601-55. 2008
  2. pmc Molecular population genetics of inversion breakpoint regions in Drosophila pseudoobscura
    Andre G Wallace
    Department of Biology, The Pennsylvania State University, University Park, Pennsylvania 16802 5301, USA
    G3 (Bethesda) 3:1151-63. 2013
  3. ncbi request reprint Evolutionary rearrangement of the amylase genomic regions between Drosophila melanogaster and Drosophila pseudoobscura
    S W Schaeffer
    Department of Biology and Institute of Molecular Evolutionary Genetics, Pennsylvania State University, 208 Erwin W Mueller Laboratory, University Park, PA 16802 5301, USA
    J Hered 94:464-71. 2003
  4. pmc Evolutionary genomics of inversions in Drosophila pseudoobscura: evidence for epistasis
    Stephen W Schaeffer
    Department of Biology and Institute of Molecular Evolutionary Genetics, Pennsylvania State University, University Park, PA 16802 5301, USA
    Proc Natl Acad Sci U S A 100:8319-24. 2003
  5. ncbi request reprint Molecular population genetics of sequence length diversity in the Adh region of Drosophila pseudoobscura
    Stephen W Schaeffer
    Department of Biology, and Institute of Molecular Evolutionary Genetics, The Pennsylvania State University, University Park, PA 16802 5301, USA
    Genet Res 80:163-75. 2002
  6. pmc Protein variation in Adh and Adh-related in Drosophila pseudoobscura. Linkage disequilibrium between single nucleotide polymorphisms and protein alleles
    S W Schaeffer
    Department of Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
    Genetics 159:673-87. 2001
  7. pmc Mechanisms of genetic exchange within the chromosomal inversions of Drosophila pseudoobscura
    Stephen W Schaeffer
    Department of Biology and Institute of Molecular Evolutionary Genetics, Pennsylvania State University, 208 Erwin W Mueller Laboratories, University Park, PA 16802 5301, USA
    Genetics 171:1729-39. 2005
  8. ncbi request reprint Selection in heterogeneous environments maintains the gene arrangement polymorphism of Drosophila pseudoobscura
    Stephen W Schaeffer
    Department of Biology and Institute of Molecular Evolutionary Genetics, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
    Evolution 62:3082-99. 2008
  9. pmc Molecular population genetics of X-linked genes in Drosophila pseudoobscura
    M Kovacevic
    Department of Biology and Institute of Molecular Evolutionary Genetics, The Pennsylvania State University, University Park, Pennsylvania 16802 5301, USA
    Genetics 156:155-72. 2000
  10. pmc Estimates of linkage disequilibrium and the recombination parameter determined from segregating nucleotide sites in the alcohol dehydrogenase region of Drosophila pseudoobscura
    S W Schaeffer
    Department of Biology, Pennsylvania State University, University Park 16802
    Genetics 135:541-52. 1993

Detail Information

Publications24

  1. pmc Polytene chromosomal maps of 11 Drosophila species: the order of genomic scaffolds inferred from genetic and physical maps
    Stephen W Schaeffer
    Department of Biology and Institute of Molecular Evolutionary Genetics, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
    Genetics 179:1601-55. 2008
    ..Despite the conservation of genes within homologous chromosome arms across species, the karyotypes of these species have changed through the fusion of chromosomal arms followed by subsequent rearrangement events...
  2. pmc Molecular population genetics of inversion breakpoint regions in Drosophila pseudoobscura
    Andre G Wallace
    Department of Biology, The Pennsylvania State University, University Park, Pennsylvania 16802 5301, USA
    G3 (Bethesda) 3:1151-63. 2013
    ..These data do not fully support the idea that genetic exchange is the sole force that influences genetic variation on inverted chromosomes. ..
  3. ncbi request reprint Evolutionary rearrangement of the amylase genomic regions between Drosophila melanogaster and Drosophila pseudoobscura
    S W Schaeffer
    Department of Biology and Institute of Molecular Evolutionary Genetics, Pennsylvania State University, 208 Erwin W Mueller Laboratory, University Park, PA 16802 5301, USA
    J Hered 94:464-71. 2003
    ..melanogaster or D. pseudoobscura lineage. The predicted genes within the 73A and 78C regions show patterns of molecular evolution in synonymous and nonsynonymous sites that are consistent with previous studies of these two species...
  4. pmc Evolutionary genomics of inversions in Drosophila pseudoobscura: evidence for epistasis
    Stephen W Schaeffer
    Department of Biology and Institute of Molecular Evolutionary Genetics, Pennsylvania State University, University Park, PA 16802 5301, USA
    Proc Natl Acad Sci U S A 100:8319-24. 2003
    ..pseudoobscura have emerged as suppressors of recombination to maintain positive epistatic relationships among loci within gene arrangements that developed as the species adapted to a heterogeneous environment...
  5. ncbi request reprint Molecular population genetics of sequence length diversity in the Adh region of Drosophila pseudoobscura
    Stephen W Schaeffer
    Department of Biology, and Institute of Molecular Evolutionary Genetics, The Pennsylvania State University, University Park, PA 16802 5301, USA
    Genet Res 80:163-75. 2002
    ..Genome rearrangement and size-dependent intron evolution are proposed as mechanisms that limit runaway intron expansion...
  6. pmc Protein variation in Adh and Adh-related in Drosophila pseudoobscura. Linkage disequilibrium between single nucleotide polymorphisms and protein alleles
    S W Schaeffer
    Department of Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
    Genetics 159:673-87. 2001
    ..The implication of this study is that linkage disequilibrium mapping has the highest probability of success with disease-causing alleles at frequencies of 10%...
  7. pmc Mechanisms of genetic exchange within the chromosomal inversions of Drosophila pseudoobscura
    Stephen W Schaeffer
    Department of Biology and Institute of Molecular Evolutionary Genetics, Pennsylvania State University, 208 Erwin W Mueller Laboratories, University Park, PA 16802 5301, USA
    Genetics 171:1729-39. 2005
    ..At least one case where selection rather than proximity to an inversion breakpoint is responsible for reduction in polymorphism was identified...
  8. ncbi request reprint Selection in heterogeneous environments maintains the gene arrangement polymorphism of Drosophila pseudoobscura
    Stephen W Schaeffer
    Department of Biology and Institute of Molecular Evolutionary Genetics, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
    Evolution 62:3082-99. 2008
    ..pseudoobscura gene arrangement polymorphism. Models of local adaptation predict that the new inversion mutations were able to invade populations because they held combinations of two to 13 local adaptation loci together...
  9. pmc Molecular population genetics of X-linked genes in Drosophila pseudoobscura
    M Kovacevic
    Department of Biology and Institute of Molecular Evolutionary Genetics, The Pennsylvania State University, University Park, Pennsylvania 16802 5301, USA
    Genetics 156:155-72. 2000
    ..The reduced heterogeneity in esterase 5 is due either to its location near one of the Sex-ratio inversion breakpoints or that it is closely linked to a gene or genes responsible for the Sex-ratio meiotic drive system...
  10. pmc Estimates of linkage disequilibrium and the recombination parameter determined from segregating nucleotide sites in the alcohol dehydrogenase region of Drosophila pseudoobscura
    S W Schaeffer
    Department of Biology, Pennsylvania State University, University Park 16802
    Genetics 135:541-52. 1993
    ..The most likely explanation for the two clusters of linkage disequilibria is epistatic selection between sites in the cluster to maintain pre-mRNA secondary structure...
  11. pmc Nucleotide sequence analysis of Adh genes estimates the time of geographic isolation of the Bogota population of Drosophila pseudoobscura
    S W Schaeffer
    Department of Biology, Pennsylvania State University, University Park 16802
    Proc Natl Acad Sci U S A 88:6097-101. 1991
    ..This divergence time suggests that D. pseudoobscura extended its range from North America to South America in a period of Pleistocene glaciation, when habitat suitable for the species presumably existed in lowland Central America...
  12. pmc Estimates of gene flow in Drosophila pseudoobscura determined from nucleotide sequence analysis of the alcohol dehydrogenase region
    S W Schaeffer
    Department of Biology, Pennsylvania State University, University Park 16802
    Genetics 132:471-80. 1992
    ..pseudoobscura. The nucleotide diversity data is consistent with direct and indirect measures of gene flow that show extensive dispersal between populations of D. pseudoobscura...
  13. pmc Polymorphism and divergence at a Drosophila pseudogene locus
    J K Pritchard
    Department of Biology, Pennsylvania State University, University Park 16802, USA
    Genetics 147:199-208. 1997
    ..Because the Lcp psi lies in a region of relatively infrequent recombination, we suggest that the low level of within-species polymorphism is the result of background selection...
  14. pmc Molecular population genetics of an electrophoretically monomorphic protein in the alcohol dehydrogenase region of Drosophila pseudoobscura
    S W Schaeffer
    Department of Biology, Pennsylvania State University, University Park 16802
    Genetics 132:163-78. 1992
    ..The neutral mutation parameter for synonymous sites is heterogeneous between domains of the Adh region. These data indicate that selective constrains on synonymous sites can vary between functional domains...
  15. pmc Molecular population genetics of sex determination genes: the transformer gene of Drosophila melanogaster
    C S Walthour
    Department of Biology, Pennsylvania State University, University Park 16802
    Genetics 136:1367-72. 1994
    ..The lack of variability in the tra gene is consistent with a recent selective sweep of a beneficial allele in or near the tra locus...
  16. pmc Adaptive evolution of genes duplicated from the Drosophila pseudoobscura neo-X chromosome
    Richard P Meisel
    Intercollege Graduate Program in Genetics, The Pennsylvania State University, PA, USA
    Mol Biol Evol 27:1963-78. 2010
    ....
  17. pmc Sulfide binding is mediated by zinc ions discovered in the crystal structure of a hydrothermal vent tubeworm hemoglobin
    Jason F Flores
    Department of Biology, Pennsylvania State University, University Park, PA 16802, USA
    Proc Natl Acad Sci U S A 102:2713-8. 2005
    ..pachyptila hemoglobins by addition of a thiol inhibitor were also unsuccessful. These findings challenge the currently accepted paradigm of annelid hemoglobin evolution and adaptation to reducing environments...
  18. pmc Meiotic transmission of Drosophila pseudoobscura chromosomal arrangements
    Richard P Meisel
    Intercollege Graduate Program in Genetics, Institute of Molecular Evolutionary Genetics, and Department of Biology, Pennsylvania State University, University Park, Pennsylvania, United States of America
    PLoS ONE 2:e530. 2007
    ..pseudoobscura inversion system are most likely due to fitness differences of gene arrangement karyotypes in different environments...
  19. ncbi request reprint The ornithine decarboxylase gene of Trypanosoma brucei: Evidence for horizontal gene transfer from a vertebrate source
    Carolyn Steglich
    Department of Biology, Slippery Rock University, Slippery Rock, PA 16057, USA
    Infect Genet Evol 6:205-19. 2006
    ..brucei, and Trypanosoma cruzi supports the hypothesis of loss of the Odc gene in the Trypanosoma lineage followed by acquisition of a new copy from a vertebrate host in the African branch of the genus...
  20. ncbi request reprint Environmental differences in hemoglobin gene expression in the hydrothermal vent tubeworm, Ridgeia piscesae
    Susan L Carney
    Department of Biology, The Pennsylvania State University, University Park, PA 16802 5301, USA
    Comp Biochem Physiol B Biochem Mol Biol 146:326-37. 2007
    ..These data demonstrate that local environmental factors influence not only phenotype but gene expression and its resulting physiological outcome within this unique species...
  21. ncbi request reprint Evolution of genes and genomes on the Drosophila phylogeny
    Andrew G Clark
    Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853, USA
    Nature 450:203-18. 2007
    ..These may prove to underlie differences in the ecology and behaviour of these diverse species...
  22. pmc Chromosomal rearrangement inferred from comparisons of 12 Drosophila genomes
    Arjun Bhutkar
    Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138, USA
    Genetics 179:1657-80. 2008
    ..On the other hand, an analysis of the disruption of syntenic blocks between species allowed the identification of fixed inversion breakpoints and estimates of breakpoint reuse and lineage-specific breakpoint event segregation...
  23. pmc Comparative genome sequencing of Drosophila pseudoobscura: chromosomal, gene, and cis-element evolution
    Stephen Richards
    Human Genome Sequencing Center and Department of Molecular and Human Genetics, Baylor College of Medicine, Houston Texas 77030, USA
    Genome Res 15:1-18. 2005
    ..Overall, a pattern of repeat-mediated chromosomal rearrangement, and high coadaptation of both male genes and cis-regulatory sequences emerges as important themes of genome divergence between these species of Drosophila...
  24. pmc Divergence between the Drosophila pseudoobscura and D. persimilis genome sequences in relation to chromosomal inversions
    Mohamed A F Noor
    Biology Department, Duke University, Durham, North Carolina 27708, USA
    Genetics 177:1417-28. 2007
    ..This reliance highlights the need for complementary genomic and population genetic approaches for tackling fundamental evolutionary questions such as speciation...