genetic grouping, on a par with Ashkenazim or Icelanders
Knowing that someone has substantial Ashkenazim ancestry lets you make many probabilistic predictions about both neutral and significant genetic variations (e.g. diseases, lactose tolerance, etc). This is because of the fact that historically mating behavior was highly nonrandom across geographical and ethnic lines. Since selection pressures and new mutations varied by region (see lactose tolerance, malaria resistance, fast-twitch muscle, salt retention, etc, etc) the differences predicted are enri... (read more)
Knowing that someone has substantial Ashkenazim ancestry lets you make many probabilistic predictions about both neutral and significant genetic variations (e.g. diseases, lactose tolerance, etc). This is because of the fact that historically mating behavior was highly nonrandom across geographical and ethnic lines. Since selection pressures and new mutations varied by region (see lactose tolerance, malaria resistance, fast-twitch muscle, salt retention, etc, etc) the differences predicted are enri... (read more)