We're Closely Related But That May Be Changing

Steve Jones reports at telegraph.co.uk on the reality of the human race, and how closely we're related in some cases, but that the trend is towards an increase in genetic diversity.

Islanders, from the Orkneys to the Adriatic (together with natives of the Americas, which was, until Columbus, the biggest and most isolated island in the world) have lots of such things – evidence of plenty of sex within the family, no doubt because no other option was available.

Across the world, such patterns match those of surnames. A fifth of all Chinese – three hundred million people – share three names, evidence of how connected lineages have become since the titles first appeared millennia ago. In France, the average number of bearers of a particular surname is 17, and in Britain it is 28. In China, the number is 70,000 (which almost reconciles me to being a Jones).

He goes on to discuss genetic diseases. 

A new survey of this kind involved 5,000 random (and supposedly unrelated) Europeans. It revealed hundreds of thousands of previously unknown family links among them, even if one goes back no further than ninth cousins (whose shared ancestor lived at around the time of the French Revolution).

There were, for example, around 30,000 predicted fourth-cousin pairs (a shared great-great-great-grandparent). As a result, taking all family ties into account, the person you sat next to on the bus this morning is, on average, likely to be something like your sixth cousin, which means that the two of you probably share at least one ancestor from the time of the Paris Commune.

You don't have to go too far back in the family tree to find close relatives.

Finns (who have a history separate from that of the rest of the continent) and Ashkenazi Jews are even more likely to have close family ties; while in parts of Pakistan, the average relationship of two random people is that of second cousins, with their common ancestor alive at the time of the fall of France.

Sir Thomas Beecham (had he ever met a Pakistani, or even a Welshman) would no doubt have been outraged. But he can begin to cheer up, for in the Western world incest (or at least inbreeding) is on the way out. The proportion of people who identify themselves as of mixed race in Britain has almost doubled in the past couple of decades, and one household in eight contains members of different ethnic origins. For about half of the nation’s children with an Afro-Caribbean parent, the other parent is white, so that on these islands the pedigrees of two continents will soon merge. The process actually began long ago: seven Yorkshiremen bear the surname Revis (after Rievaulx Abbey in the county). Each carries a Y chromosome that came from West Africa, perhaps in the 18th century. It is now being joined by millions more.

Just think... there used to be people who prohibited interracial dating, marriages, and parenting, but children of interracial parents were actually the least likely to have parents who were committing "incest."

His overall point is that for much of human history, people in various regions have been closely related, but now with increased mobility that is changing. I'll point out, though, that studies still show that most people are attracted to people who look like them and that that the increased mobility is one of the factors that is going to lead to an increase in cases of Genetic Sexual Attraction. In the past, when a performing artists, sailor, soldier, other traveling professional, or a tourist became a party to a conception, there was little chance the parent would see their progeny, and even less of a chance that other children of parent would meet up with that progeny. Same thing when divorcing parents have moved thousands of miles apart and had children with new spouses. That's not so anymore.