I guess the whole world knows that King Richard III’s skeleton has been found in Leicester. Two things about it particularly interested me.
The first was that the person whose drive brought about the discovery, Pippa Langley, turnes out to be an acquiantance of my brother, much to his surprise. The second, of more general application, was the announcement that there was a DNA match between the bones and a descendant of Richard’s sister.
How much DNA counts as a match, I wonder? I ask because if we assume the sister in question to have been born around 1450, we can estimate that there have elapsed perhaps 25 generations leading to the lucky heir. And that means he has 2^25, or 33,554,432 ancestors of that generation. Or to put it another way, statistically it is likely that a majority of the indigenous population of Britain is also descended from Mary’s sister to the same extent.
Unless, of course, that particular line kept on marrying their siblings.