Research Topics
| S Blair HedgesSummaryAffiliation: Pennsylvania State University Country: USA Publications
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Detail Information
Publications
Wormholes record species history in space and timeS Blair Hedges
Department of Biology, Pennsylvania State University, University Park, PA 16802, USA
Biol Lett 9:20120926. 2013..These data also provide evidence for historians in determining the place of origin or movement of a woodblock, book, document or art print...- Amniote phylogeny and the position of turtlesS Blair Hedges
Department of Biology, Pennsylvania State University, University Park, PA 16802 5301, USA
BMC Biol 10:64. 2012..in BMC Biology, place turtles with birds and crocodilians. Molecular studies have not wavered as the numbers of genes and species have increased, but morphologists have been reluctant to embrace the molecular tree... 
Molecular phylogeny and biogeography of West Indian frogs of the genus Leptodactylus (Anura, Leptodactylidae)S Blair Hedges
Department of Biology, 208 Mueller Laboratory, Pennsylvania State University, University Park, PA 16802 5301, USA
Mol Phylogenet Evol 44:308-14. 2007..The relatively minor genetic differentiation of populations of L. albilabris can be explained by vicariance and dispersal in the Pleistocene and Holocene, although human introduction of some populations cannot be ruled out...- TimeTree: a public knowledge-base of divergence times among organismsS Blair Hedges
Department of Biology, Pennsylvania State University, University Park, PA 16802 5301, USA
Bioinformatics 22:2971-2. 2006..AVAILABILITY: TimeTree is available at http://www.timetree.net.. - A molecular phylogeny of reptilesS B Hedges
Department of Biology, Institute of Molecular Evolutionary Genetics, and Astrobiology Research Center, 208 Mueller Laboratory, Pennsylvania State University, University Park, PA 16802, USA
Science 283:998-1001. 1999..Morphological and paleontological evidence for this molecular phylogeny is unclear. Molecular time estimates support a Triassic origin for the major groups of living reptiles... - Precision of molecular time estimatesS Blair Hedges
NASA Astrobiology Institute and Department of Biology, Pennsylvania State University, University Park, PA 16802-5301, USA
Trends Genet 20:242-7. 2004 - A molecular timescale of eukaryote evolution and the rise of complex multicellular lifeS Blair Hedges
NASA Astrobiology Institute and Department of Biology, The Pennsylvania State University, University Park, PA 16802, USA
BMC Evol Biol 4:2. 2004..Here, we used all available protein sequence data and molecular clock methods to place constraints on the increase in complexity through time... - Comparison of mode estimation methods and application in molecular clock analysisS Blair Hedges
NASA Astrobiology Institute and Department of Biology, Pennsylvania State University, 208 Mueller Laboratory, University Park, PA 16802 5301, U, S, A
BMC Bioinformatics 4:31. 2003..We compared these methods in simulations to determine their strengths and weaknesses and further assessed their performance when applied to real data sets from a molecular clock study... - Genomic clocks and evolutionary timescalesS Blair Hedges
NASA Astrobiology Institute and Department of Biology, 208 Mueller Laboratory, Pennsylvania State University, University Park, PA 16802 5301, USA
Trends Genet 19:200-6. 2003..Fortunately, time estimates inferred using many genes or proteins have greater precision and appear to be robust to different approaches... - A genomic timescale for the origin of eukaryotesS B Hedges
Astrobiology Research Center and Department of Biology, 208 Mueller Laboratory, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
BMC Evol Biol 1:4. 2001..We used refined methods of sequence alignment, site selection, and time estimation to address these questions with protein sequences from complete genomes of prokaryotes and eukaryotes... - The origin and evolution of model organismsS Blair Hedges
NASA Astrobiology Institute and Department of Biology, 208 Mueller Laboratory, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
Nat Rev Genet 3:838-49. 2002..This emerging comparative framework and the emphasis on historical patterns is helping to bridge barriers among organism-based research communities... - Evolutionary sequence analysis of complete eukaryote genomesJaime E Blair
NASA Astrobiology Institute, Department of Biology, The Pennsylvania State University, 208 Mueller Laboratory, University Park, Pennsylvania 16802 5301, USA
BMC Bioinformatics 6:53. 2005..We apply this approach to complete sets of proteins from published eukaryote genomes specifically for phylogeny and time estimation... - The phylogeny of squamate reptiles (lizards, snakes, and amphisbaenians) inferred from nine nuclear protein-coding genesNicolas Vidal
Department of Biology, Astrobiology Research Center, Pennsylvania State University, University Park, PA 16802 5301, USA
C R Biol 328:1000-8. 2005..Molecular time estimates show that the Triassic and Jurassic (from 250 to 150 Myr) were important times for squamate evolution and diversification... - Major Caribbean and Central American frog faunas originated by ancient oceanic dispersalMatthew P Heinicke
Department of Biology, Pennsylvania State University, University Park, PA 16802 5301, USA
Proc Natl Acad Sci U S A 104:10092-7. 2007..Origin by dispersal, probably over water from South America in the early Cenozoic (47-29 million years ago, Mya), is more likely... - Molecular phylogeny and divergence times of deuterostome animalsJaime E Blair
NASA Astrobiology Institute and Department of Biology, The Pennsylvania State University, University Park, USA
Mol Biol Evol 22:2275-84. 2005..We found that most major lineages of deuterostomes arose prior to the Cambrian Explosion of fossils (approximately 520 MYA) and that several lineages had originated before periods of global glaciation in the Precambrian... - Genomics. Vertebrate genomes comparedS Blair Hedges
NASA Astrobiology Institute and Department of Biology, 208 Mueller Laboratory, Pennsylvania State University, University Park, PA 16802-5301, USA
Science 297:1283-5. 2002 - Molecular phylogeny and biogeography of the Antillean geckos Phyllodactylus wirshingi, Tarentola americana, and Hemidactylus haitianus (Reptilia, Squamata)Andrew J Weiss
Department of Biology, 208 Mueller Lab, Pennsylvania State University, University Park, PA 16802, USA
Mol Phylogenet Evol 45:409-16. 2007 
A major clade of prokaryotes with ancient adaptations to life on landFabia U Battistuzzi
Department of Biology, Pennsylvania State University, USA
Mol Biol Evol 26:335-43. 2009..These results now leave open the possibility that terrestrial adaptations may have played a larger role in prokaryote evolution than currently understood...- The colonization of land by animals: molecular phylogeny and divergence times among arthropodsDavide Pisani
NASA Astrobiology Institute and Department of Biology, The Pennsylvania State University, University Park, PA 16802, USA
BMC Biol 2:1. 2004..Nine nuclear and 15 mitochondrial genes were used in phylogenetic analyses and 61 genes were used in molecular clock analyses... - Molecular evidence for a terrestrial origin of snakesNicolas Vidal
NASA Astrobiology Institute and Department of Biology, 208 Mueller Laboratory, Pennsylvania State University, University Park, PA 16802, USA
Proc Biol Sci 271:S226-9. 2004..Here, we show that DNA sequence evidence does not support a close relationship between snakes and monitor lizards, and thus supports a terrestrial origin of snakes... - The phylogeny and classification of caenophidian snakes inferred from seven nuclear protein-coding genesNicolas Vidal
Department of Biology and NASA Astrobiology Institute, 208 Mueller Lab, Pennsylvania State University, University Park, PA 16802 5301, USA
C R Biol 330:182-7. 2007..The phylogeny also indicates that, ancestrally, caenophidian snakes are Asian and nocturnal in origin, although living species occur on nearly all continents and are ecologically diverse... - A genomic timescale of prokaryote evolution: insights into the origin of methanogenesis, phototrophy, and the colonization of landFabia U Battistuzzi
NASA Astrobiology Institute and Department of Biology, 208 Mueller Laboratory, The Pennsylvania State University, University Park, PA 16802, USA
BMC Evol Biol 4:44. 2004..We assembled a data set of sequences from 32 proteins (approximately 7600 amino acids) common to 72 species and estimated phylogenetic relationships and divergence times with a local clock method... - Origin of invasive Florida frogs traced to CubaMatthew P Heinicke
Department of Biology, 208 Mueller Laboratory, The Pennsylvania State University, University Park, PA 16802, USA
Biol Lett 7:407-10. 2011..The subtropical Keys may have served as an adaptive stepping stone for the successful invasion of the North American continent... - The evolutionary position of nematodesJaime E Blair
Astrobiology Research Center and Department of Biology, The Pennsylvania State University, University Park, PA 16802, USA
BMC Evol Biol 2:7. 2002..Traditionally, nematodes have occupied a basal position, in part because they lack a true body cavity. However, the leading hypothesis now joins nematodes with arthropods in a molting clade, Ecdysozoa, based on data from several genes... - Biogeography: the coelacanth of frogsS Blair Hedges
Nature 425:669-70. 2003 - Molecular clocks do not support the Cambrian explosionJaime E Blair
Mol Biol Evol 22:387-90. 2005..With these results aside, molecular clocks continue to support a long period of animal evolution before the Cambrian explosion of fossils... - Constraining fossil calibrations for molecular clocksS Blair Hedges
Bioessays 28:770-1; author reply 772-3. 2006 - Pushing back the expansion of introns in animal genomesSudhir Kumar
Center for Evolutionary Functional Genomics, Biodesign Institute, and School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA
Cell 123:1182-4. 2005..These observations suggest that the common ancestor of most animal phyla had intron-rich genes and reinforce the notion that introns proliferated early in the evolutionary history of eukaryotes... - Higher-level relationships of snakes inferred from four nuclear and mitochondrial genesNicolas Vidal
Service de systématique moléculaire, Institut de systématique CNRS FR 1541, Museum national d histoire naturelle, 43, rue Cuvier, 75231 Paris, France
C R Biol 325:977-85. 2002..Consequently, the macrostomatan condition should not be treated a priori as a derived character state devoid of homoplasy... - Early evolution of the venom system in lizards and snakesBryan G Fry
Australian Venom Research Unit, Level 8, School of Medicine, University of Melbourne, Parkville, Victoria 3010, Australia
Nature 439:584-8. 2006..These results provide new insights into the evolution of the venom system in squamate reptiles and open new avenues for biomedical research and drug design using hitherto unexplored venom proteins... - Higher-level relationships of caenophidian snakes inferred from four nuclear and mitochondrial genesNicolas Vidal
Service de systématique moléculaire, Institut de systématique CNRS FR 1541, Museum national d histoire naturelle, 43, rue Cuvier, 75231 Paris, France
C R Biol 325:987-95. 2002..The front-fanged venom system appeared three times independently. The active diurnal foraging mode (associated with a high metabolic rate) appears in a derived position among colubroids... - Placing confidence limits on the molecular age of the human-chimpanzee divergenceSudhir Kumar
Center for Evolutionary Functional Genomics, Biodesign Institute, and School of Life Sciences, Arizona State University, Tempe, AZ 85287 5301, USA
Proc Natl Acad Sci U S A 102:18842-7. 2005..We conclude that tests of hypotheses about the timing of human-chimpanzee divergence demand more precise fossil-based calibrations... - Origin of tropical American burrowing reptiles by transatlantic raftingNicolas Vidal
Departement Systematique et Evolution, UMR 7138, Systématique, Evolution, Adaptation, Case Postale 26, Museum national d histoire naturelle, 57 rue Cuvier, 75231 Paris Cedex 05, France
Biol Lett 4:115-8. 2008..Until now, only four or five transatlantic dispersal events were known in terrestrial vertebrates. Significantly, this is the first such dispersal event to involve a group that burrows, an unexpected lifestyle for an oceanic disperser... - The platypus is in its place: nuclear genes and indels confirm the sister group relation of monotremes and TheriansTeun van Rheede
Department of Biochemistry, Radboud University Nijmegen, Nijmegen, The Netherlands
Mol Biol Evol 23:587-97. 2006..The morphological evidence for a basal position of Monotremata, well separated from Theria, is thus fully supported by the available molecular data from nuclear genes...