From the Jesus Dynasty Blog (March 13th 2007): “I have just discussed today in an earlier post that the DNA tests on the bone fragments from this ossuary would have shown two individuals, or more, if they were mixed together in one ossuary. The ancient DNA found showed only one person, unrelated maternally to Yeshua son of Joseph.”
The first fact to start with, is that only mitocondrial DNA was successfully retrieved from ossuaries in the Talpiot Tomb.
From my short but still serious two years of college education in Biology, there are some basic facts about DNA that I am quite certain about. Nuclear DNA is unique for every person, so tests can distinguish individuals, one from the other. However, nuclear DNA was not successfully retrieved from any ossuary in the tomb.
On the other hand, mitochondrial DNA was retrieved from two ossuaries. Mitochondrial DNA is always identical among members of single maternal line. Therefore, mitochondrial DNA tests can only distinguish individuals born of different mothers (or more precisely from a different maternal lines), but cannot distinguish individuals born of the same mother/maternal line. Both male and female members of the same maternal line have identical DNA in their mitochondria. This is because each of the numerous mitochondrial organelles found in each cell contain identical DNA, and multiply independently of the cell’s nucleus. Since these are found in the mother’s eggs but not in the father’s sperm, the organelles, along with their identical DNA, are passed on to the children unchanged from their mother and then through the daughters from generation to generation. The fact that only one type of mytochondrial DNA could be identified in the ossuary could mean any of the following:
1) The two individuals Mariame and Mara were two sisters born of the same mother.
2) The two individuals Mariame and Mara were mother and daughter, or mother and granddaughter, etc.
3) The two individuals Mariame and Mara were female relatives of the same maternal line.
4) Not all bone fragments and organic sources in the ossuary were actually tested by the lab.
5) Even if five individuals, or parts thereof, were originally in the same ossuary, potentially, none of the others survived (or the entire remains of other individuals may have been removed.)
In the light of the fact that there are two names written on this inscription, I think the first option is the most preferable scenario (over against numbers 2 and 3), although one must still take into account numbers 4 and 5.