In a joint 2000 paper in Science, Poinar and Dr. Alan Cooper argued that much existing work in human ancient DNA has not been sufficiently rigorous to prevent DNA contamination from modern human sources, and that many reported results for ancient human DNA may therefore be suspect.[6]
In 2003, Poinar and others from the Max Planck Institute published genetic sequences isolated from coprolites of the extinct Shasta giant ground sloth,[4] with an estimated age of 10500 years using radiocarbon dates. These were the first genetic sequences retrieved from any extinct ground sloth.[7]
In September 2008, Poinar's laboratory published results showing that after a long period of separation in the mammoth populations of Siberia and North America, the Siberian mammoth population had been completely replaced by mammoths of North American origin.[8][9][10]
In 2014, Poinar and colleagues published the first genomic data from victims of the Plague of Justinian in Bavaria, demonstrating that this plague was caused by a strain of Yersinia pestis now extinct.[11][12]
^Wagner, David M.; J. Klunk; M. Harbeck; A. Devault; N. Waglechner; J. W. Sahl; J. Enk; D. N. Birdsell; M. Kuch; C. Lumibao; D. Poinar; T. Pearson; M. Fourment; B. Golding; J. M. Riehm; D. J. D. Earn; S. DeWitte; J.-M. Rouillard; G. Grupe; I. Wiechmann; J. B. Bliska; P. S. Keim; H. C. Scholz; E. C. Holmes; H. Poinar (28 January 2014). "Yersinia pestis and the Plague of Justinian 541—543 AD: a genomic analysis". The Lancet Infectious Diseases. 14 (4): 319–26. doi:10.1016/S1473-3099(13)70323-2. PMID24480148.