How is time depth approximated in analysis of mitochondrial DNA in lineage analysis?

Question

How is time depth approximated in analysis of mitochondrial DNA in lineage analysis?

Answer 1

Time depth is approximated by mutation analysis. Over time a certain number of DNA mutations wil be incorporated into DNA just as a function of probability.

If you know that, you can use different forms a comparative genetics to gauge the sequence age of mitochondrial DNA. For example, genotype analysis of HLA (human leukocyte antigens) is used to determine when during diaspora that certain groups of individuals stopped mixing genes (mating) with certain other groups--such as when asians split from caucasians, etc...

So if you know when two groups split, you can measure the mitochondrial mutations and know that you have x number of mutations over the length of time that those people split from each other.  

Hope that helps.