Title |
The colonization of land by animals: molecular phylogeny and divergence times among arthropods
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Published in |
BMC Biology, January 2004
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DOI | 10.1186/1741-7007-2-1 |
Pubmed ID | |
Authors |
Davide Pisani, Laura L Poling, Maureen Lyons-Weiler, S Blair Hedges |
Abstract |
The earliest fossil evidence of terrestrial animal activity is from the Ordovician, approximately 450 million years ago (Ma). However, there are earlier animal fossils, and most molecular clocks suggest a deep origin of animal phyla in the Precambrian, leaving open the possibility that animals colonized land much earlier than the Ordovician. To further investigate the time of colonization of land by animals, we sequenced two nuclear genes, glyceraldehyde-3-phosphate dehydrogenase and enolase, in representative arthropods and conducted phylogenetic and molecular clock analyses of those and other available DNA and protein sequence data. To assess the robustness of animal molecular clocks, we estimated the deuterostome-arthropod divergence using the arthropod fossil record for calibration and tunicate instead of vertebrate sequences to represent Deuterostomia. Nine nuclear and 15 mitochondrial genes were used in phylogenetic analyses and 61 genes were used in molecular clock analyses. |
X Demographics
Geographical breakdown
Country | Count | As % |
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United States | 1 | 100% |
Demographic breakdown
Type | Count | As % |
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Members of the public | 1 | 100% |
Mendeley readers
Geographical breakdown
Country | Count | As % |
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Germany | 9 | 3% |
United States | 8 | 2% |
United Kingdom | 7 | 2% |
Brazil | 5 | 1% |
Mexico | 3 | <1% |
Argentina | 3 | <1% |
Portugal | 2 | <1% |
Colombia | 2 | <1% |
Canada | 2 | <1% |
Other | 4 | 1% |
Unknown | 290 | 87% |
Demographic breakdown
Readers by professional status | Count | As % |
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Researcher | 79 | 24% |
Student > Ph. D. Student | 58 | 17% |
Student > Master | 39 | 12% |
Student > Bachelor | 28 | 8% |
Professor | 25 | 7% |
Other | 72 | 21% |
Unknown | 34 | 10% |
Readers by discipline | Count | As % |
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Earth and Planetary Sciences | 32 | 10% |
Biochemistry, Genetics and Molecular Biology | 16 | 5% |
Environmental Science | 10 | 3% |
Social Sciences | 4 | 1% |
Other | 21 | 6% |
Unknown | 42 | 13% |