Parental percentages on Gedmatch

[irenych]

Is it correct to assume that if an offspring has 25% of a particular value, say "West Asian", on a given chromosome, while a tested parent has 5% "West Asian" on the same chromosome, then the excess percentage (and perhaps more) must have come to the offspring from the other parent?

[irenych]

Is it correct to assume that if an offspring has 25% of a particular value, say "West Asian", on a given chromosome, while a tested parent has 5% "West Asian" on the same chromosome, then the excess percentage (and perhaps more) must have come to the offspring from the other parent?

I am assuming of course that the other parent is unavailable for testing. The answer would seem obvious to me, but in these matters many apparently obvious things may not be. Hence the query.

[thetick]

I don't understand the details of you question. Segments (parts of chromosomes) are passed either from the father or the mother. I don't understand what you mean by values with percentages and geographical locations.

[irenych]

I don't understand the details of you question. Segments (parts of chromosomes) are passed either from the father or the mother. I don't understand what you mean by values with percentages and geographical locations.

Gedmatch uses Dienekes' nomenclature. "West European" "East European" "Mediterranean" etc. I assumed that if the total "West European" in a particular chromosome, say chromosome 5, from the tested mother was 40% (Gedmatch analysis) and 50% in the offspring in the same chromosome, then the difference would have come from the other parent.

[thetick]

Gedmatch uses Dienekes' nomenclature. "West European" "East European" "Mediterranean" etc. I assumed that if the total "West European" in a particular chromosome, say chromosome 5, from the tested mother was 40% (Gedmatch analysis) and 50% in the offspring in the same chromosome, then the difference would have come from the other parent.

OK I see. We no since you only get 50% of your SNP from one parent and we know they are NOT distributed evenly over a chromosome.

So in the extreme case for illustration: a mother being Chinese and German and a father being African and Indian.

They could in theory have two drastically different children

One with 50% Chinese and 50% African and the other child 50%German and 50% Indian. Now most likely one would get children with 25% each but if you go down to chromosomal level a child certainly could but rarely get a complete chromosome from one parent. All degrees in between and including the extreme and the 25% average are possible.

So the answer is most likely percentage-wise yes, but there could be drastic variations.

[irenych]

So the answer is most likely percentage-wise yes, but there could be drastic variations.

Understood. In any case, the principle that a parent cannot pass on more than he or she has applies.