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Why do the standard paternity tests not notice when someone is effectively the child's uncle? The genes must match to a far greater extent than an "unrelated" p
by Jabbles 11y ago
Why do the standard paternity tests not notice when someone is effectively the child's uncle? The genes must match to a far greater extent than an "unrelated" person. Is that information lost between the actual test and the "yes/no/probability" result?
- jfoutz 11y agoBrothers and sisters only share 1/4th dna. brother A gets 50% of dad's genes. Brother B also gets 50%, but not (necessarily) the same 50%. same process on the mothers side.
- Udik 11y agoSo it's 1/2 shared dna for siblings, not 1/4th. Only (I think, possibly) it's 1/2 on average instead of being exactly 1/2 as in the case of parents and children.
- jfoutz 11y agoAh, I did the table wrong in my head. You're right. 2 genes, one from father one from mother, sibling A along the top, simbling A down the side. MM MF FM FF MM 1 .5 .5 0 MF .5 1 0 .5 FM .5 0 1 .5 FF 0 .5 .5 1 (4+ .5 * 8 + 0)/16 = 8/16 = 1/2
- waqf 11y agoThey share ½. Half-siblings share ¼ dna, because of exactly what you said. Full siblings share half of the half they got from their father, plus half of the half they got from their mother, for a total of ½. An uncle and nephew, as in the article, would share ¼.