Since we are all related. Let's assume the first human being was African and let's assume they were of the "black race". Then would it not be possible for the whitest, fairest, most caucasion of parents, to give birth to a black baby? Because there must be black genes in the gene pool somewhere. And has it ever happened? Or do I not understand genetics at all?
Yes, all humans have the same genes, or some variation of them. However, the environment in which the fetus develops plays a very important role in how those genes are expressed. This is what affects the appearance of the child -- not which genes they have, for the most part, but how they are expressed.
I would say no, not really. You appear to be struggling with some basic concepts behind inheritance of traits. IMO this is the best online genetics tutorial I have come across. I recommend it for people who want to learn the basic concepts behind genetics. In your case you should start with the “classical genetics” section. http://www.dnaftb.org/dnaftb/
What is it, do we have the same genes or a variation? What "environment" do you need so that two African Americans can have a Asian baby?
Same genes, different alleles. You would need an asian woman's womb (a surrogate mother, perhaps). This won't create an asian baby, but it could change the how the baby would look compared to if it developed in an african woman's womb.
no you have to have a recent african relative to aquire the features, my wife is caribbean and i am russian with southern european. there is no way our child can come out african or japanese. and no carribean black people are not the same race as africans, they either decent from arawak tribes or carib tribes. slaves from africa came over to the islands but are not the same as true caribbean people. many people get caribbean and african origins mixed up due to lack of understanding. and call them all "black" wich is offensive to alot of people. many caribbean people do not like being called african. just like im sure canadians dont like being called americans. or english people being called french. peace.
if I marry a girl who lives on Mars in environment of orange dust skies under umbrella of life supporting system. Will my baby be Martian and the soul in his eyes will reflect all the environment?
Racial features characterized by recessive alleles can "hide" in a person apparently of another "race" - which means that two apparently black parents who each carry hidden recessive alleles for white features could, if the shuffle worked out just right, have a white baby. The reverse would be more difficult, as most of the alleles for black features in most "races" of black people are not recessive when paired with white feature alleles, and so would not be hidden in the parents.
Blacks directly from African descent do not carry recessive alleles for white features; likewise those of direct Caucasian descent do not carry alleles for black features. Evolution is a slow process that gradually isolated races: now we intermix.
wow, there is a lot of confusion going back and forth here. All humans have roughly the same number of chromosomes and genes. There is variation between populations and individuals, and there are genetic disorders which change the total number of genes, and which are usually detrimental - often fatal. In most humans, however, there are 24 chromosome pairs, for a total of (very roughly) 3,000,000,000 base DNA pairs. Individuals and populations can have different alleles and different versions of genes coding for different traits, but by and large, we have very very similar DNA. When a phenotype change occurs in a population (e.g. an average darkening of the skin) that can happen in a number of places inclusively between DNA and the skin pigment itself. 1) The length of time pigment proteins are allowed to exist once created. Every protein in the body has a shelf-life, and is destroyed after a while. The longer a given type of protein hangs around, the more of it can accumulate. 2) The length of time tRNA hans around. m- and t-RNA are in charge of actually building proteins from genetic code, in a process called transcription. Then longer these molecules hang around, the more work they end up doing. 4) Expression of RNA - once the RNA is created, it can be expressed or not. I'm not as familiar with th current understanding of how this is regulated, so I won't try to explain this 5) Expression of DNA - recent studies suggest that even the "dormant" DNA, sections that do not result in protein formation, are still partially translated into RNA. During this process, however, the RNA is not completed, and with the job half done, the RNA doesn't produce any proteins, and so the DNa is not "expressed". Now if a mutation to an active DNA region occurs (a genotype change), and it actually has an effect on the resulting proteins (many mutations have no protein coding effect *at all*), then it either shuts off protein creation, reduces protein creation, increases protein creation, or it alters the protein itself. During the long isolations of human populations in the past tens of thousands of years, certain groups have seen collections of genetic mutations unique to their groups. So an Asian man will have genetic characteristics not found in African or European men, and vise versa. Those genetically encoded changes (as opposed to expression changes based on environmental factors) do not exist everywhere, and so no, an African couple cannot produce an Asian child. The gene versions are not present for that to be possible. HOWEVER, there is more genetic variation between individuals than there is between "races", so this is no different than saying that two people with green eyes (recessive trait) cannot have a child with brown eyes. nor is it claiming any significant value in dividing people into groups based on skin color or skeletal structure. http://en.wikipedia.org/wiki/Dominance_relationship valich is correct, though I would in a large part disagree with Idle Mind's assertion that a surrogate mother of a different race would in any significant measure effect the fetus. Barring conflicts like rH factor between mother and child, the placenta provides a fairly good barrier between the two distinct living organisms.
Let's say two unrelated couples, each a black and white couple, had a mixed child - one a boy, one a girl and these two mated when they reached adulthood. Would they be able to have a white and black child as well as mixed?
The Gene which makes white sheep white is dominant over that which produces Black sheep I don't know whether the wool from Black sheep was more prized than white, but in the nusery rhyme it was the Black sheep which was asked for its wool. With white and black people, neither is dominant, they usually produce coffee coloured children. Its only a Gene which regulates the amount of melanin produced in the skin as a reaction to sunlight. It has nothing to do with race in people.
To expand on Chris Cremin's reply, IIRC, the two types of melanin involved in human skin pigmentation are controlled by either four or five genes which work together via an incomplete dominance setup. Children of a light-skinned person and a dark-skinned person tend to be a mixed shade somewhere in between, due to the complex combination of these genes. To go further, let me define something - the original two couples, each couple containing one theoretically extreme 'white' (all genes coding for the least amount of pigmentation) and one theoretically extreme 'black' individual (all genes coding for the maximum amount of pigmentation), is called the 'p1' generation. The kids they produce are the 'f1' generation, their kids are 'f2'. We aren't going to discuss the topic further, but beyond that, there is 'f3', 'f4', 'f5'.... So your question of the "f2" generation (children of the children of the starting pairs) is not as simple as Mendel's pea matrices, with whom everyone with a fair amount of biology education will be familiar, and which dealt mainly with single genes in complete dominance situations. Using Punnett Squares http://en.wikipedia.org/wiki/Punnett_square , we can map out the possible genetic combinations for the offspring of a pair of individuals similarly to how he mapped out pea combinations - though in cases of incomplete dominance such as this, they get pretty complicated http://en.wikipedia.org/wiki/Incomplete_dominance#Incomplete_dominance. I'm not going to do up an entire Punnett square here, but I'll try and summarize the important combinations below. Edit: the following is a simplified mental exersize which ignores a number of factors of incomplete dominance, chromosomal location, any effects of epistasis, imprinting, and more. You will pass an intro-level genetics course with this logic, you'll fail a grad-school level class with it, though. Understand it, then go learn more and figure out where it's incomplete. When the p1 couples reproduce, their offspring (the f1 generation) will be all 50/50 genetically. Since they get one copy of each of the five genes from each parent, they will receive one "light" version and one "dark" version of each of the five melanin-controlling genes. As such, their skin color will be a perfect middle-ground in all ways. Now, in reality, the theoretical extreme 'white' and 'black' p1 individuals are not very common, so don't get too hung up on this mental exersize. When these two f1 individuals produce offspring, they have a 50 chance to provide either a light or a dark version of each gene, so the possible gametes they can produce would be: all light, 1/5 dark, 2/5 dark, 3/5 dark, 4/5 dark, all dark. Since any of the 5 genes can be the 'odd man out', it's much more likely that some mixture will occur than one extreme end or the other will result (there is only one way that "all light" can occur - there are 5 possible ways that 1/5 dark can occur, and 10 ways that 2/5 dark can occur. Only 2 gametes out of every 32 produced would be all light or all dark - a 1/16th chance). It is possible, though not very common, that the two f1 individuals would together create a single f2 recombination that is genetically identical to one of the original p1 grandparents (extreme light or extreme dark). Namely, the two gametes which result in a child would need to both, by random 1/16th chance, provide all light or all dark genes. It would then, by random chance, have to come about that both gametes are the *same* extreme versions, and as such, the f2 offspring would end up with all light or all dark-encoding genes, just like a grandparent of the p1 group. (edit: if my math is right, then 2 out of every 1024 kids in the f2 generation will be extreme light or extreme dark, like the p1 members) As a final note, it should be remembered that albinism is another issue that must be considered; there an otherwise genetically dark individual can have very light colored skin due to a defect in melanin creation - this is a different genetic situation than the genetic light skinned people described above in p1. http://en.wikipedia.org/wiki/Human_skin_color
