A concern about the breach of privacy emerged almost immediately. Though I have serious reservations about the sensationalism which BritainsDNA has engaged in, I think it is totally legitimate of them to infer William’s ancestry in the fashion they did. First, Prince William is a public person, and in direct line to the throne of the United Kingdom. Though some of the spin may be distasteful, remember that this is a person who is where he is because of his ancestry. Second, anyone who performs genealogical research is exposing the information of family members, often without their consent. If William’s mtDNA haplogroup was known to be pathogenic than the case for withholding the information from the public seems straightforward. As it is all that was uncovered was relatively banal, that William may have a South Asian ancestress. There’s a lot of information about me that I’d rather not others know first, but that’s not how the world works. In the grand scheme of things this just isn’t a big deal, and we should focus on the more concrete problem of public understanding of science, and long term issues in regards to genetic privacy more generally.
Addendum: I am aware of concerns in regards to paternity. On the whole I generally think in most situations this is probably information that is going to come out in any case, and so it wouldn’t hurt for it to emerge earlier. Additionally, in the cases of historical figures such as Thomas Jefferson’s presumed line of descent there were widely diverging views among the white descendants as to whether they should cooperate because of the possible moral implications. I suspect most would agree it is better to know this information, even though it implied that line of putative black Jefferson descendants may have paternity misassignment in their lineage. Finally, obviously these issues are far diminished in the case of mtDNA, since maternity is guaranteed. Though one never knows if someone who was adopted was never told of his reality.
Image credit: Wikimedia
A few years ago I blogged a paper on how inbred the last Spanish Habsburgs had become, leading to all sorts of ill effects. Take a look at Charles II of Spain! He was as inbred as the product of a sibling mating. An extreme case of pedigree collapse in humans if there was one. This came to mind when an amusing feature in The Philadelphia Inquirer popped into my RSS feed, In royal/commoner marriage, a happy mix of genetic diversity. The writer gets a good number of choice quotes from one of the coauthors of the Habsburg paper, who observes that Prince Charles is moderately inbred, but his pairing with the very distantly related Diana (who came from the nobility as well) basically meant that his sons were outbred. Nevertheless, there is the suggestion that extra genetic diversity can’t hurt. I don’t think this is really a major positive worth mentioning. First, there is the possibility of outbreeding depression. Honestly I doubt this will be an issue. But secondly, I think more relevant is that gains to outbreeding hit massive diminishing marginal returns rather quickly. For example, here’s the coefficient of relationship between pairs of relatives:
0.5 = Full siblings, parent-child
0.25 = Half siblings, Uncle/aunt-niece/nephew
0.125 = First cousins
0.03125 = Second cousins
0.0078125 = Third cousins
As you can see the genetic relevance of relatedness really drops off rapidly in a conventionally outbred population. There isn’t much gain I’d say to Prince William marrying a female who has a greater genetic distance from him. Though the marriage of a common Englishwoman, Kate Middleton, into the British royal family moves it further on from its relatively recent dominant German character.