The point here is, they are asking us to eliminate the only answer that is not possible. I got it wrong. read well fellas
The pedigree presents us with Male-to-Male transmission. There are two modes of inheritance where Male-to-Male transmission is impossible: 1) X-linked recessive 2) Mitochondrial inheritance
My understanding is that if parents are unrelated by blood to those affected, we assume that they are not carriers (in the recessive case). Therefore, if we have a male father affected with x-linked recessive married to a non-carrier, there's no way any of his offspring would be affected.
"If one parent is not a carrier, then a child can only inherit a disease allele from the other parent. In these problems, we can assume that any individual marrying into the family is not a carrier." https://www.cs.cmu.edu/~genetics/units/instructions/instructions-CP.pdf
x-linked is not possible if the woman was not a carrier autosomal recessive is not possible if the woman was not a carrier so, why we choose x-linked
I thought there weren't supposed to be trick questions on these things.
No one talks about AR? That's much more unlikely in this case than XR
I got thrown off because there's an arrow point to the three unaffected daughters (with an affected father) so I thought XLR because they'd be carriers. And there was no generation skipping so that made me think AR
This is the 3rd question I didn't read properly fk fk fkityfk
submitted by stars and more(16)
X linked recessive there can never be any Male to Male transfer since the male offspring gets Y from father. the pedigree shows Male to Male transmission so this cannot be X linked recessive