S
Stephen J. O'Brien
Researcher at Saint Petersburg State University of Information Technologies, Mechanics and Optics
Publications - 1074
Citations - 98793
Stephen J. O'Brien is an academic researcher from Saint Petersburg State University of Information Technologies, Mechanics and Optics. The author has contributed to research in topics: Population & Gene. The author has an hindex of 153, co-authored 1062 publications receiving 93025 citations. Previous affiliations of Stephen J. O'Brien include University College Cork & QIMR Berghofer Medical Research Institute.
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Journal ArticleDOI
Molecular Genetics and Evolution of Melanism in the Cat Family
Eduardo Eizirik,Naoya Yuhki,Warren E. Johnson,Marilyn Menotti-Raymond,Steven S. Hannah,Stephen J. O'Brien +5 more
TL;DR: The inferred multiple origins and independent historical elevation in population frequency of felid melanistic mutations suggest the occurrence of adaptive evolution of this visible phenotype in a group of related free-ranging species.
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Unique seminal quality in the South African cheetah and a comparative evaluation in the domestic cat.
David E. Wildt,R. Mitchell Bush,JoGayle Howard,Stephen J. O'Brien,D. Meltzer,A. van Dyk,H. Ebedes,D. H. Brand +7 more
TL;DR: Results indicate that seminal characteristics in the cheetah are markedly inferior compared to the domestic cat, particularly with respect to the incidence of pleiomorphic spermatozoa.
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Elephant Seal Genetic Variation and the Use of Simulation Models to Investigate Historical Population Bottlenecks
A. R. Hoelzel,John M. Halley,Stephen J. O'Brien,Claudio Campagna,T. Arnborm,BJ Le Boeuf,Katherine Ralls,Gabriel A. Dover +7 more
TL;DR: DNA sequence diversity in two mtDNA regions was investigated and found low genetic variation in the northern elephant seal: there were only two control region haplotypes (sequence difference = 1%), which was consistent with an extreme founder event in the recent history of the northern species.
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Influence of seasonal migration on geographic distribution of mitochondrial DNA haplotypes in humpback whales.
C. S. Baker,Stephen R. Palumbi,R. H. Lambertsen,M. T. Weinrich,John Calambokidis,Stephen J. O'Brien +5 more
TL;DR: A marked segregation of mitochondrial DNA haplotypes among subpopulations as well as between the two oceans is reported, interpreted to be the consequence of maternally directed fidelity to migratory destinations.
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Phylogeography and genetic ancestry of tigers (Panthera tigris).
Shu-Jin Luo,Shu-Jin Luo,Jae Heup Kim,Jae Heup Kim,Warren E. Johnson,Joelle M. van der Walt,Joelle M. van der Walt,Janice S. Martenson,Naoya Yuhki,Dale G. Miquelle,Olga Uphyrkina,John M. Goodrich,Howard B. Quigley,Ronald Tilson,Gerald Brady,Paolo Martelli,Vellayan Subramaniam,Charles McDougal,Sun Hean,Shi Qiang Huang,Wenshi Pan,Ullas K. Karanth,Melvin E. Sunquist,James L. Smith,Stephen J. O'Brien +24 more
TL;DR: To investigate the species' evolutionary history and to establish objective methods for subspecies recognition, voucher specimens of blood, skin, hair, and/or skin biopsies from 134 tigers with verified geographic origins or heritage across the whole distribution range were examined for molecular markers.