All the DNA proves is that the family was related. It doesn't prove which family it is.
So, they claim that based on some register of names, drawing each name randomly, the chance of those names all popping up is 1 in 600.
So basically, they are saying that 1 in 600 families had those names.
Which, sounds like a rare occurrence, but it is not, because of course there were a lot more than 600 families in Jerusalem at the time.
"Which, sounds like a rare occurrence, but it is not, because of course there were a lot more than 600 families in Jerusalem at the time."
Not to mention that the historical family was poor (and thus tombless) and lived in Nazareth, by way of Bethlehem, (and thus any tomb would have been there), looking at a Jeruselem tomb is patently silly.