In a nutshell, inbreeding increases the odds of rare genetic disorders because the more closely related two people are, the more likely it is that they’ll both be carriers of the same recessive genes, which gives these genes a chance of pairing up.
However, it’s important to note that even if both parents are carriers of disorder-linked recessive genes, odds are that their offspring will not develop the disorder. In other words, while inbreeding increases this risk, it’s not guaranteed.Emphasis ours. The fact is, most children born to close relatives are healthy. It's also important to remember that consanguinamory and inbreeding aren't the same thing, though inbreeding can result from consanguinamory.
Then the blog has a YouTube video from ASAP Science on the topic.
For more, please see our entry on Consanguinamory and Reproduction and this entry for consanguinamorists considering parenting.
https://www.popsci.com/marrying-cousins-genetics
ReplyDeleteOdds are against it, yes. But the odds are still not good. For brother-sister and parent-offspring couples, they're about one in three.
ReplyDeleteYou're right. But that is not the same for first cousins. First cousins have a very low risk and it should not be compared to other kinds of risk. Also.. I'm talking single generation only. Multiple generations inbreeding in the same family can easily raise those initial risks and is generally the reason there are so many negative examples of incestuous reproduction in history (like royal lineages that have several consanguineous marriages in one line, leading to unhealthy offspring or people with defects).
DeleteSingle generation reproduction vs multiple generation, cousins vs other types of relatives are very VERY different things. Much of the misinformation out there comes from failing to make a distinction between these things.
For first-generation cousins, the additional risk works out to about 4% absolute. Other numbers are harder to get.
DeleteDISAGREED WITH THE WORD INCEST OR INCESTUOUS CAUSE ITS ABOUT SOMETHING THAT IS RELATED TO RAPING THEIR OWN FAMILY MEMBERS. CONSANGUINAMORY IS VERY CONFUSING TO EVERYONE. CONSANGUINAMORY IS NOT CHAOS, ITS LOVE.
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