Paternity test question

You have two recently collected DNA samples, let’s say hair samples, of a father and a son, both of when the men were age 40 or so. If they are unmarked, is possible to determine which is the parent and which is the descendant? Try to explain in layman’s terms how this is possible, please. Not that I’d expect anyone to tell the difference from my usual natterings but I’m very slow on the uptake this evening.

If the hair looks alike, no, unless skin tabs exist on the hair. This is where we find the DNA. Of course if one is blond and the other is brunette.

neat trick. :dubious:

Let me rephrase. A father’s DNA sample is taken at age 40. Decades later his son’s sample is taken, also at age 40. The two samples are mixed up. The samples should show there’s a genetic match between the two – but is tiere a way to determine which is the father’s and which is the son’s by the evidence of just those two samples, or would a third sample (say the son’s mother) be needed? Why or why not?

Forget "hair.’

I don’t think you can tell from just the two sets of genes.

The two individuals (X & Y) will have 50+ % of the genes in common (the greater than half due to father and mother coincidentally having some matching allelles) but this could be due to either:

X is father, and one half of his genes were passed along to his son, Y


X is the son, and one half of his genes were inherited from his father, Y.

OTOH, if you had one male and one female, you COULD tell which is parent and child by looking at the genes in the mitochondria.

From what I’ve read, mitochondria are inherited solely in the egg, so if the two have matching mitochondria, then the female is the mother. If they differ, then the female is the daughter.
And you couldn’t tell with two females, either: the mitochondria will match, regardless of which is which.
Not that you asked about these other two cases, I just thought it was interesting.