Genectics(ish?) question
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13-04-2012, 03:54 PM
Genectics(ish?) question
Long time no talk guys. Been busy with school, hope you're all doing well. Big Grin
Anyways, I have a question that came into my mind.

So I'm dating a girl who is mixed race (dad is black, mom is white) and I was wondering, if I had a child with her, what are the chances of the child being white and the chances of the child being black? I realize with this set-up I'd have to do one of those Punnet Square things (I'm assuming I'd be dominant white skin but idk what hers would be).. I'm a bit confused on how that would be set-up exactly. Also, I tried googling it and got no straight answers lol


Hopefully this post doesn't come off as racist or anything but I'm just curious. And don't worry I won't get her pregnant
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13-04-2012, 09:06 PM
RE: Genectics(ish?) question
Let's ASSUME both parents are homozygous in gene colour, and that only one gene controls skin colour. Let's also assume that the gene is co-dominant.

Let B be the dominant gene for black skin colour
W be the dominant gene for white skin colour

Parental Phenotype: Black x White
Parental Genotype: BB x WW
F1 Offspring Genotype: All BW
F1 Offspring Phenotype: All Mixed

F1 Parental Phenotype: Mixed x White
F1 Parental Genotype: BW x WW
F1 Parental Gametes: (B) (W) and (W)

Offspring Genotypic Ratio: 1 BW : 1 WW
Offspring Phenotypic Ratio: 1 Mixed : 1 White

50% Mixed, 50% White.

(Remember that the numbers I get is based on various assumptions, in which in reality genes coding for skin colour are most likely follow continuous variation. There is still a chance that you can get a child with black skin colour)

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14-04-2012, 12:28 PM
RE: Genectics(ish?) question
Ahhh gotcha. It's been awhile since I've done this stuff in school. Thanks for the help.
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14-04-2012, 06:52 PM
RE: Genectics(ish?) question
It doesn't work that way; you are asking the wrong question.

The children will not be 'black' or 'white'.

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14-04-2012, 07:01 PM
RE: Genectics(ish?) question
If you're going to use the old US Jim Crow laws about who is black and who is white, it might be an issue, but otherwise, why the fuck would you even spend more than 5 seconds thinking about it? Assuming you lover her, that is.

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14-04-2012, 07:17 PM
RE: Genectics(ish?) question
This sounds like my half sister's family, she has siblings on her mom's side (we have the dame dad) where some are straight haired, some are kinky haired, varying skin tones, etc. Her kids all have olive skin tones and straight course hair, one has brown eyes and two have blue eyes.

Really, for you guys, anything can happen.
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14-04-2012, 10:03 PM
RE: Genectics(ish?) question
Skin color is a polygenic (controled by many genes) trait. The expressed phenotype would be determined by the combination of those genes relative to the dominant and recessive aspect of each individual genotype. You cannot do a single Punnet square to figure out your scenario, it would take many.

The combination of these genes determines the level of melanin that your skin cells produce to enhance the skin's protection from UV rays. The common statement is that our population will someday show no variation in skin color (all humans will be a tan color), which is a fallacy. Do some research on the Hardy-Weinberg principle to learn how the allele frequency within a population fluctuates. I do not feel that our species will reach that point unless certain events occur (genetic bottlenecking). It's fun to think about what might be, but we can never be 100% sure.
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15-04-2012, 07:30 AM
RE: Genectics(ish?) question
They will most likely be dark skinned but whiter in colour than Their granddad. I'm sure that genes for darker skin is dominant but I'd need to check that.

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15-04-2012, 12:16 PM
RE: Genectics(ish?) question
(15-04-2012 07:30 AM)FSM_scot Wrote:  They will most likely be dark skinned but whiter in colour than Their granddad. I'm sure that genes for darker skin is dominant but I'd need to check that.
This seems to be the best answer.
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07-07-2012, 03:16 AM
RE: Genectics(ish?) question
(14-04-2012 07:01 PM)Erxomai Wrote:  If you're going to use the old US Jim Crow laws about who is black and who is white, it might be an issue, but otherwise, why the fuck would you even spend more than 5 seconds thinking about it? Assuming you lover her, that is.
sorry for late response but this has been bothering me..

Like I said I don't really care if they're black or white and I'm not really trying to be racist or anything which is why i apologized in the first place if it came off like that. It was just a question that popped into my head and figured it would be a good way to expand my knowledge on traits a little bit .. sure maybe using the terms black and white isn't something I should say if I'm not trying to come off as racist I realize now, so sorry if I offended anyone or came off as rude but I didn't want to dodge the question. If I cared about black and white do you really think I'd be dating a girl who is both? come on now

Thank you for the answers though everyone. Smile
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