For example, during pregnancy African Americans are said to have a higher chance of getting preeclampsia or gestational diabetes. Genetically, what’s happening here?
In: 72
Usually, these increased chances relate to a genetic bottleneck event. This is where a relatively small population of an animal (including humans) expand and colonize an entire area with their relatively small basket of genes. This most often happens with migration where a small group moves to a new area but occasionally happens when a population is almost completely wiped out and then regrows.
Black Americans are a perfect example. The millions of modern black Americans often trace their heritage to a fairly small number of captured and trafficked slaves. The Africans who were trafficked to America weren’t picked randomly from the genetically diverse population of western Africa. They were usually specific towns, tribes, clans, or other distinct populations. Often people who were already related to each other through generations of living in the same region.
So if a particular clan of people, by random chance, carry a gene that predisposes them to a health problem like diabetes or pre-eclampsia, and they get trafficked to America, suddenly you have an oddity where a very large proportion of the black slaves in America have that gene. That population wasn’t allowed much travel. Wasn’t allowed to marry anyone outside or their group. But did expand into millions of people. And so you end up with millions of people who have a weirdly high rate of a particular gene because that gene happened to get kidnapped onto a slave ship a couple centuries ago.
Latest Answers