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13 Genetic Mutations That Can Arise from Incest

Updated October 26, 2018 12.7m views13 items

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.

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  • Microcephaly

    Photo: Internet Archive Book Images / flickr / No known copyright restrictions

    Based on social mores, among Pakistani Muslims, intermarrying with close blood relatives, like first cousins, still takes place, and the impact is becoming visible. A 1998 study demonstrated that about 63% of Pakistanis participate in blood-relative marriages, which contributed to a rise in a condition called microcephaly, where a child is born with an unusually small head. This often means that the brain does not fully develop, either. As such, mild to severe mental disabilities are a major risk. The inbreeding in Pakistani culture means that 1 in 10,000 Pakistanis have this problem, compared to the 1 in 1,000,000 people who have it in the general global population.

  • Cleft Palate

    King Tut, who was born of incest, showed a surprising number of medical problems when his body was examined, including cleft palate. A cleft palate occurs when the roof of the mouth does not form fully, and is thus left open to the sinus passage. This makes eating, swallowing, breathing, and even speaking difficult.

  • Clubfoot

    Photo: Internet Archive Book Images / flickr / No known copyright restrictions

    This is another disorder found in King Tut, and it is yet another example of how incest can impact the genetics of children. Club foot describes a broad range of different foot abnormalities, but it generally can be noted by the tendons that connect the foot to the body being too short to allow the foot to rest flat. These conditions are present at birth, and are certainly not solely caused by incest. However, close genetic linkages between parents can increase the risk of the condition.

  • Albinism

    Photo: angs school / flickr / CC-BY-NC-ND 2.0

    Albinism is a condition where your body lacks melanin, a substance that causes your hair, skin, lips, and other body parts to have color. People with albinism tend to have light eyes, pale skin, and near-white hair, even if they come from a dark-skinned heritage. This condition is an autosomal recessive disease, which means that when people with similar genes breed, their children are more likely to have it. Cousins, siblings, and parent/children unions are far more likely to express this type of condition, as evidenced by what happens in small breeding pools.

    Puerto Rico, for example, contains small pockets of people that rarely get much genetic diversity, and it has the highest density of albinism in the world.