Random Genetic tree question

psd99

psd99

psd99

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trying to workout something really random but here is the place for it.......................

A 100% chinese woman marries a 100% Affrican man they have kids so that makes their kid 50% chinese and 50% African

Said kid then decides that he marries a 100% chinese woman, they have kids - so I take it those kids are now 75% chinese 25% african.

Now what I don't understand is say that kid (third generation) decides to marry a chinese woman again what ratio would their kids be?

I'm trying to workout what this is all called? and at what stage do the kids end up being 100% chinese, is this even possible?

/random thread over.. cue the silly replies yes but please don't be racist!!!!
 
it's a series that will never reach 0, assuming each successive generation breeds with pure chinese then there will never be a pure chinese child from the coupling.

however that's just in a purely theoretical sense, in a practical sense there comes a point where you can't measure the difference and therefore for all intents and purposes you'd say 100%.

now genetics can be funny, with dominant and recessive genetic traits it's possible that some features will never dissappear or indeed dissappear faster.

so no, yes, maybe depending on how deep you want to go.

reminds me of the german "purity" test, where if you had a parent/grandparent then you were a jew (with all the repurcussions that might have in nazi germany), but of course if your grandfather had a jewish grandfather then he was a jew, and by extension so were you, cue people trying to pull their family tree back hundreds of years in order to prove they were "pure".
 
Assuming that a child is exactly half of each parent for this:

100% african father + 100% chinese mother = (0.5 x 0.0) + (0.5 x 1.0) = 0.5 (50% chinese)
that 50% chinese child then has kids with 100% chinese mother = (0.5 x 0.5) + (0.5 x 1.0) = 0.75 (75% chinese children)
those 75% chinese children then have kids with 100% chinese mother = (0.5 x 0.75) + (0.5 x 1.0) = 0.875 (87.5% chinese)
(0.5 x 0.875) + (0.5 x 1.0) = 0.9375 (93.75%)
(0.5 x 0.9375) + (0.5 x 1.0) = 0.96875 (96.875%)

You'll get the sequence by doing:
0.5-(0.5^n) + 0.5 where n is the number of generations.
 
Last edited:
touch said:
Assuming that a child is exactly half of each parent for this:

100% african father + 100% chinese mother = (0.5 x 0.0) + (0.5 x 1.0) = 0.5 (50% chinese)
that 50% chinese child then has kids with 100% chinese mother = (0.5 x 0.5) + (0.5 x 1.0) = 0.75 (75% chinese children)
those 75% chinese children then have kids with 100% chinese mother = (0.5 x 0.75) + (0.5 x 1.0) = 0.875 (87.5% chinese)
(0.5 x 0.875) + (0.5 x 1.0) = 0.9375 (93.75%)
(0.5 x 0.9375) + (0.5 x 1.0) = 0.96875 (96.875%)

You'll get the sequence by doing:
0.5-(0.5^n) + 0.5 where n is the number of generations.
Click to expand...

Thanks that's exactly what I needed!!! wow
 
@psd99
I'm not sure on the genetics but lets treat ethnicity as an entirely measurable and inheritable trait.

The child of the 100%X dad and the 100%Y mom will be 50:50 X and Y and lets assume she is a girl to make the story easier to follow.

If the 50:50 girl child has children with a 100% X father then their child will have 50%X from dad and somewhere between 50% X to 50% Y from Mom assuming the genes she passes on are equally likely to be given.

So there would be a bell curve of likely outcomes from 100% X at one extreme to 50:50 X-Y at the other extreme with the average outcome 75%X 25% Y.

Does that sound right?

It's not a simple halving because probability comes into it.
 
TheOracle said:
aren't we all part african anyway?
Click to expand...

Certainly one of the lines of though was spread from that region up and through was what a differently shaped middle/east/Europe, passing east and onwards around the globe.
It is quite interesting, as I think they state that sub-Saharans wouldn't descent from the tribes that moved north, but remain in the region, or south of the region.
I am unsure with the progression of the aborigine line, however.
NZ conforms to the islands base for DNA progression iirc, down through Indonesia, the pacific islands, over to Hawaii etc, but I think the aboriginal subset is quite distinct.

I've always been fascinated by this, but never really had the time to research it properly, with geological maps to show where and how the drift and separations of landmasses were and would be.
 
The question doesn't really work at all well because things such as "Chinese" and "African" aren't simple discrete genetic groupings.

One way of trying to make some sort of approximation of genetic groupings is using haplogroups, but that's not the same thing at all and does not conform to modern national or continental boundaries.
 
PlacidCasual said:
[The child of the 100%X dad and the 100%Y mom will be 50:50 X and Y and lets assume she is a girl to make the story easier to follow.
Click to expand...

Top tip: don't use X and Y as variables like this when discussing heredity. I thought you were going to make a point about differential inheritance of X and Y chromosomes.
 
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