[AdmSmith]

There are two kinds of DNA, nuclear DNA and mitochondrial DNA. Researchers study mitochondrial DNA, usually, not nuclear DNA, although I am not sure why.

The mitochondrion is the power central of the cell and there are varying number of them in different cell types, with more of them in muscle cells etc.

The likelihood of recovering mitochondrial DNA, mtDNA in small or degraded biological samples is greater than for nuclear DNA because mtDNA molecules are present in hundreds to thousands of copies per cell compared to the nuclear complement of two copies per cell. Thus is is easier to study and get the information from mtDNA.

However, phylogenic studies are as well done on the Y-chromosome and so you can as well find a pedigree tree on the fathers side.

[donh]

There are two kinds of DNA, nuclear DNA and mitochondrial DNA.

There's one kind of DNA known, and some DNA chromosomes are packaged for work in the nucleous, and some kinds are packaged for work in mitochondria, and some kinds are packaged for work in other organelles, as well.

From evaluations of numerous critters we know--thanks to various mutational distance calculations now available to us, to be in our predecessor chain--that we have been steadily leaking chromosome packages out of their mitocondrial containers and into the nucleous over time. Quite a trip for a chromosome, in my humble opinion.