Incest is a taboo in pretty much every culture around the world, but it wasn't always so. Nobles and royals used to try to keep royal blood pure by marrying people they were related to; Egyptians rulers, in particular, would often marry their siblings or even their own children. This gave us a glimpse of the serious genetic mutations that can arise from incest. But how exactly do you get genetic problems from incest?
Even if there's not always a mutation, inbreeding with someone you're related to brings up a lot of problems involving recessive traits. Because the two of you have similar genes, any recessive abnormalities you have can be passed on more easily and expressed more visibly in your offspring. This also means that, even if you don't show any signs of genetic disorders yourself, your child may show incest-related genetic mutations. It is important to note that these traits and mutations don't always arise from incest, but they can show up more frequently through incestuous breeding.
If you're still morbidly curious as to how incest affects your genes or what inbred people look like, look no further. Here are just a few of the genetic mutations that come from incest, as well as the expression of recessive genes you might never see otherwise.
Immune System DisordersPhoto: Benjamin von Block / via Wikimedia
Children born of incest tend to be very sickly. While this may have to do with malformations of the skeleton, muscles, or organs, a major factor is a faulty immune system. In a properly functioning immune system from a non-incestuous pairing, there's a wide range of different alleles that fight off different diseases - the wider the variety, the more diseases you can combat. When you breed with a close blood relative, though, the resulting immune system has far fewer unique alleles and can only protect itself from a smaller set of diseases. This lack of diversity makes a child much more susceptible to diseases, and can effectively stunt the immune system.
We may not fully understand how the body passes on immunity from parent to child, but historically speaking, it's pretty obvious that incest does not help. Our DNA needs diversity in order to build a strong immune system.