Experts in ancient DNA from McMaster University (Canada) have teamed up with genome researchers from Penn State University (USA) for the investigation of permafrost bone samples from Siberia. The project also involved paleontologists from the American Museum of Natural History (USA) and researchers from Russia, the United Kingdom, France, and Germany.
The researchers' report on the first genomic sequences from a woolly mammoth will be published on 22 December 2005 by the journal Science on the Science Express website. This majestic mammal roamed grassy plains of the Northern Hemisphere until it became extinct about 10,000 years ago.
The scientific breakthrough allows for the first time comparion of this ancient species with today's populations of African and Indian elephants, not just at the level of mitochondrial sequences, but also encompassing information from the nuclear genome.
Analyzing organellar DNA from mitochondria has been the only method of studying ancient DNA in the past, as it is more tractable due to its 1000-fold higher copy number per cell. However, the mitochondrial genome codes for only a tiny fraction of an organism's genetic information -- 0.0006 percent in the case of a mammal.
In contrast, most hereditary information is organized on chromosomes located in the cell's nucleus (nuclear DNA). A mammoth was chosen for study in part because of its close evolutionary relationship to the African elephant, whose nuclear DNA sequence has been made publicly available by the Broad Institute in Cambridge, Massachusetts (USA). Using comparisons with elephant DNA, the researchers identified 13 million base pairs as being nuclear DNA from the mammoth, which they showed to be 98.5 percent identical to nuclear DNA from an African elephant.
Tag : DNA, Biology, Science, Africa.