4 ms·

You share (about) 1/128 of your genes with a third cousin. The chance of any (particular) recessive trait being passed on from both parents as a result of the

You share (about) 1/128 of your genes with a third cousin. The chance of any (particular) recessive trait being passed on from both parents as a result of the inbreeding is a whopping 1 in 65,536.

kkarakk 8y ago
it says in the article that their second kid was autistic.
- raverbashing 8y ago
  Given that its causes are still not fully understood I think blaming it on a 3rd degree connection is a bit of a stretch
- philpem 8y ago
  The root cause of which is -- at least as far as I'm aware -- currently unknown to medical science. It could be a recessive trait (1 in 65536 doesn't mean "impossible")... but it could also be one of a near-infinite number of other possibilities.
- spacehome 8y ago
  I guess there’s a chance those facts are related.
  - loseyourslinky 8y ago
    Giving birth after 35 (in this case 37) is statistically more risky than offspring from first cousin's. A third cousin is much more distantly related than a first cousin, your first cousin has a pair of the same grandparents as you, your third cousin shares a pair of your Great-great-grandparents.
stromgo 8y ago
I'm not sure what you computed. The interesting question is to pick a recessive trait from one of the parents and ask for the chance of it being passed on. The probability that it's being passed on from the parent who has it is 1/2. The probability that it's being passed on from the other parent is (1/2)*(1/128). The combined probability is 1/512, not 1/65,536.
Veen 8y ago
I'm not an expert on this, so perhaps you could tell me if a family history of cousin marriage increases the likelihood of the recessive trait being passed by both parents. I mean, if for the last 10 generations a family has been marrying cousins to each other and introducing little variation from people outside the family, the odds are increased, right? I'd imagine cultures with a history of cousin marriage, such as the Pakistani community in the UK, are much more prone to this type of problem than when cousins marry, but none of their forbears married a cousin.
- kwhitefoot 8y ago
  Yes. See, for instance, https://www.researchgate.net/publication/8326382_Influence_of_ethnic_origin_on_the_incidence_of_keratoconus_and_associated_atopic_disease_in_Asian_and_white_patients https://www.researchgate.net/publication/8326382_Influence_o... and for some wider background and reassurance see: https://www.researchgate.net/publication/38114212_Commentary_The_background_and_outcomes_of_the_first-cousin_marriage_controversy_in_Great_Britain https://www.researchgate.net/publication/38114212_Commentary...

You share (about) 1/128 of your genes with a third cousin. The chance of any (particular) recessive trait being passed on from both parents as a result of the inbreeding is a whopping 1 in 65,536.

kkarakk 8y ago

it says in the article that their second kid was autistic.

raverbashing 8y ago
Given that its causes are still not fully understood I think blaming it on a 3rd degree connection is a bit of a stretch
philpem 8y ago
The root cause of which is -- at least as far as I'm aware -- currently unknown to medical science. It could be a recessive trait (1 in 65536 doesn't mean "impossible")... but it could also be one of a near-infinite number of other possibilities.
spacehome 8y ago
I guess there’s a chance those facts are related.
- loseyourslinky 8y ago
  Giving birth after 35 (in this case 37) is statistically more risky than offspring from first cousin's. A third cousin is much more distantly related than a first cousin, your first cousin has a pair of the same grandparents as you, your third cousin shares a pair of your Great-great-grandparents.

stromgo 8y ago

I'm not sure what you computed. The interesting question is to pick a recessive trait from one of the parents and ask for the chance of it being passed on. The probability that it's being passed on from the parent who has it is 1/2. The probability that it's being passed on from the other parent is (1/2)*(1/128). The combined probability is 1/512, not 1/65,536.

Veen 8y ago

I'm not an expert on this, so perhaps you could tell me if a family history of cousin marriage increases the likelihood of the recessive trait being passed by both parents. I mean, if for the last 10 generations a family has been marrying cousins to each other and introducing little variation from people outside the family, the odds are increased, right? I'd imagine cultures with a history of cousin marriage, such as the Pakistani community in the UK, are much more prone to this type of problem than when cousins marry, but none of their forbears married a cousin.

kwhitefoot 8y ago
Yes. See, for instance, https://www.researchgate.net/publication/8326382_Influence_of_ethnic_origin_on_the_incidence_of_keratoconus_and_associated_atopic_disease_in_Asian_and_white_patients https://www.researchgate.net/publication/8326382_Influence_o... and for some wider background and reassurance see: https://www.researchgate.net/publication/38114212_Commentary_The_background_and_outcomes_of_the_first-cousin_marriage_controversy_in_Great_Britain https://www.researchgate.net/publication/38114212_Commentary...