Ancient DNA is DNA isolated from ancient specimens. It can be also loosely described as any DNA recovered from biological samples that have not been preserved specifically for later DNA analyses. Examples include the analysis of DNA recovered from archaeological and historical skeletal material, mummified tissues, archival collections of non-frozen medical specimens, preserved plant remains, ice and permafrost cores, Holocene plankton in marine and lake sediments, and so on. Unlike modern genetic analyses, ancient DNA studies are characterized by low quality DNA.
This places limits on what analyses can achieve. Furthermore, due to degradation of the DNA molecules, a process which correlates loosely with factors such as time, temperature, and presence of free water, upper limits exist beyond which no DNA is deemed likely to survive. Allentoft et al (2012) tried to calculate this limit by studying the decay of mitochondrial and nuclear DNA in Moa bones. The DNA degrades in an exponential decay process. According to their model, mitochondrial DNA is degraded to 1 base pair after 6,830,000 years at -5°C. Nuclear DNA degrades at least twice as fast as mtDNA. As such, early studies that reported recovery of much older DNA, for example from Cretaceous dinosaur remains, may have stemmed from contamination of the sample. Read more ...
DNA Study Reveals Genetic History of Europe Sci-News - April 24, 2014
An international team of scientists has used ancient DNA recovered from human remains dating from up to 5,500 BC to reconstruct the first detailed genetic history of modern Europe. The research reveals a dramatic series of events including major migrations from both Western Europe and Eurasia, and signs of an unexplained genetic turnover about 4,000-5,000 years ago. The team used DNA extracted from bone and teeth samples from prehistoric human skeletons to sequence a group of maternal genetic lineages that are now carried by up to 45 per cent of Europeans. They established that the genetic foundations for modern Europe were only established in the Mid-Neolithic, after this major genetic transition around 4,000 years ago. This genetic diversity was then modified further by a series of incoming and expanding cultures from Iberia and Eastern Europe through the Late Neolithic
Fossilized human feces found in Oregon cave Global Post - July 16, 2012
New fossilized DNA found in Oregon is proving that humans lived in cave dwellings as early as 14,300 years ago, the Associated Press reported. The DNA was extracted from coprolites, otherwise known as fossilized feces. Along with the coprolites, stone points were discovered in the same cave. The points found in the cave differ from those used by the Clovis people, once thought to be the first North Americas, suggesting that this tribe lived at the same time, or possibly before, the Clovis people.
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