[medhahegde]

Handling ancient DNA is extremely challenging, from finding sufficient material to start with, until eliminating the contamination caused by various sources including modern human beings. Some damages to the DNA also cause changes in its sequence. Cytosine can convert to uracil, which is recognised by copying enzymes as thymine, which results in a C to T transition. Similarly changes from Guanine to Adenine also occur. Errors in the DNA molecule are very frequent at the ends.

During the early years, the study of genetic material from the ancient specimens was predominantly dedicated to investigate the DNA sequence of many extinct species, for instance Woolly Mammoth and Dodo. But during recent years the scientists are beginning to ponder on new question regarding ancient DNA revealing how the genetic constitution of prehistoric populations has changed through the time scale. And these findings will help scientists to unfold evolution.

Characterizing between the ancient genetic material and that of modern humans is particularly complicated when the aDNA comes from close relatives of modern human population. During the current years, ancient DNA has been utilized in the understanding of aspects biology of the Neanderthals. The sequencing of the mitochondrial (mtDNA) and nuclear DNA extracted from fossils have furnished information regarding the speech, appearance, capability and population structure of Neanderthals in addition to their phylogenetic relationship with the modern human beings.

Ancient DNA (aDNA) is also being utilized to shed light regarding the origin of modern humans. The analysis of available ancient DNA has provided the evidence that mitochondrial DNA (mtDNA) from Neanderthals looked reasonably different from the mitochondrial DNA (mtDNA) of early modern human beings. And this has supported to the theory that modern humans have a single African origin rather than the alternative theory of multiregional evolution, where the theory proposes that ancestors of modern humans and Neanderthals bred in the past.