What are the specific genetics that allow a white mother and father to have a black baby?

Question

I've heard that this has happened before, but I don't understand how it is possible. Could someone explain it scientifically?

Answer 1

Define "black and white."

Skin color is a trait with many allelles.

Using X to represent a dark allele and O to represent the absence of a dark allelle, we can say that someone who was
OOOOOOOO, OOOOOOOX, OOOOOOXX,OOOOOXXX would generally be considered white and someone who was XXXXXXXX, OXXXXXXX,OOXXXXXX, OOOXXXX, would be black and someone OOOOXXXX would be difficult to characterize as either.

Since the allelles independently assort, if mom and dad were
OOOOOOOX, OOOOOOXX,OOOOOXXX they could have a kid who was as dark as from XXXXXXOO. It's like picking Xs and Os from a shoebox blindly. How they assort is random. The kid gets 4 of each from mom and 4 from dad.

Skin color does not act on simple mendelian genetics, like pea plants. It is a polygenic trait. There are at least 8 allelles that determine skin type...not one dominant and one recessive.

Look here: http://www.cliffsnotes.com/WileyCDA/CliffsReviewTopic/Principles-of-Genetics.topicArticleId-8741,articleId-8616.html

Answer 2

LabGrl has it right. At least six genes are required to produce a deep brown to black color in humans. As humans radiated northward, people who had lost some of the genes did better since they could absorb more sunlight to make vitamin D. By the time humans had gotten to the norwegian lands they had paled to almost completely white so white is the recessive form not the dominant. M1m1, M2m2, m3m3, m4m4, m5,m5 m6m6 would tan but never achieve the dark skin tone of M1m1, M2,m2, M3m3, M4m4 etc. The fact is, a complete recessive white couple could never have a darker skinned baby than themselves.

Answer 3

Lol, it's actually called recombination. Sort of like being dealt a royal straight flush in poker

The only difference between one type of skin color and the other is the concentration of melanin. We all have melanin in the skin (unless albino). And it's sort of obvious that the concentration of melanin is controlled by many genes on different allels. Basicly the baby just got enough of the high concentration melanin from both parents randomly. No magic and you don't need a hidden gene in there either.

Answer 4

The only way to explain this is that the two parents genotypes are heterozygous (Ww). 'W' meaning that white is the the dominant color and 'w' means that black is recessive. If you work it out in a punnett square, they would have a 25% chance of having a black baby.

Answer 5

that's achievable for the daddy to be black yet no longer as in all threat. whilst racism grow to be prevelant it grow to be achievable for a black mom to have a white toddler which will then bypass as white yet whose toddlers could have been black. there have been dissimilar tragedies linked with this variety of venture. the sole thank you to make effective is a dna attempt.

Answer 6

There has to be a recessive African American gene