Why are some genes exclusive to Europeans (or so it seems)?
404089
drift and/or sexual selection. Most likely sexual selection as the things you listed are essentially cosmetic.
252640
I'm also a white African and I also don't understand that. I have more African roots than most of the black African Americans, my family tree goes back 400 years. When I meet black people that's European they never call themselves African Europeans, so why do they do that in the USA. Personally I think it's causes division between different races. I thought we were trying to stop race separation, because it causes racism.
346172
Americans that are Europhobic are so because they are ignorant.  However, I do not believe being "europhobic" is the case most of the time.  I think it has to do with the many difference between the different cultures.  If you have relatives who immigrated not too long ago from Europe then you are more likely to be accepting and fit in with the European differences in our two clutures.
948983
Technically, it's somewhere between possible and likely that there were multiple original organisms, who were promiscuously swapping genetic material.  This is way back, before the eukaryotes, archea and eubacteria separated.\n\nBut yeah, all eukaryotes almost certainly descend from a single eukaryote (the integration of the first mitochrondria appears to be such an unlikely occurance that it probably only happened once)
828336
Yes, of course it does. Breeding within a limited population always increases the incidence of recessive gene expression. Interestingly, a lot of these societies practice consanguineous marriage, which further amplifies the risk.
840176
Pretty simple actually.  The original man and woman had great complexity in their genes.  When God made different languages at the tower of Babel, this divided people into groups- thus splitting the gene pool.  Different features survived better in different climates.  For example, in a hot, sunny climate people with dark skin absorbed less ultraviolet light, but people with fair skin got too much.  They either got various diseases and died, or moved to an area with shorter days.  That's just one example.  The differences that we see (skin color, hair type, etc.) is a small fraction of all the things the different "races" have in common.  There is actually only one race- the human race.  \nSkin color is what people tend to focus on the most.  But we actually all have the same skin color, caused by the pigment melanin, we just have different amounts of it. And how much is determined by genetics.  \nActs 17:26 says "and He made from one blood, every nation of mankind to live on all the face of the earth, having determined their appointed times, and the boundaries of their habitation..."\nIt's just simple genetics.  And look what we've done with it.
235952
Its true that melanin controls the color of the skin, but I assume you are asking the entire genetic difference.  First, there is no definition in science for a black or white person, and even individuals would differ in what they consider dark enough to be black, or light enough to be white- But even assuming you had a definition, based on how dark a person is, there isnt any clear genetic difference.  In fact, people from Ethiopia and Somalia are more closely related to European caucasians then they are to west African tribes.  Extremely dark people from the Indian subcontinent are closely related to Europeans, and are genetically considered nearly identical-Native Australians are not very closely related (relatively speaking) to African blacks.  The skin color of a person is only one aspect of thousands of characteristics-it just happens to be one that we can easily see.  If you look at blood types, certain african groups are more closely related to Ethnic Slavs than the slavs are to other European groups (even though the slavs "look" like other Europeans)- this is only one example of many that have been found...what a person looks like appears to have very little to do with genetic relatedness.
50708
This is really all about genetics. Each person has differing genes and inherit family traits!
110632
Homogeneous just means the same, or uniform throughout.  It doesn't necessarily apply to race.  You can certainly have a genetically homogeneous population, but that is a much higher level of sameness than a racially homogeneous population.  Within any racial group there is a huge amount of genetic variability.  \n\nOK, Kurdiatcha's response to my analysis is entirely correct. I will point out, though, that I never said it was anything other than speculation.  At any rate, I hadn't slept in about 3 days, and in that context my analysis made perfect sense to me.  Sorry!\n\nNew theory: I think the perseption that there is more physical diversity in Europe than Africa or Asia could be partially explained by the fact that Europe is geographically smaller.  So it's just that all the different groups are more crammed together and it ends up looking more diverse.\n_________\n\n>>>It was one of the better responses I’ve seen on Yahoo\n>>>answers. It just happened to be incorrect.\nSo I never use the expression "lol," but it seems rather appropriate here.  That was well said.  Thanks : )\n\nYou're probably right on my other theory too.  I should just stop speculating on this entirely.  I do want to point out, though, that the guy who posted the question and said Europeans look more different than Asians is Asian (at least he said so in another question), so I don't think you're entirely correct that people are always more tuned in to difference within their own racial group.  I wouldn't have bothered to speculate on the issue at all (after you shoot down my first theory, that is) except I thought it could possibly hold some tinsy bit of truth because of that.
812959
A " dominant " gene only means that gene is expressed. Africans have no more dominant genes than anyone else. Are you confusing a dominant gene with a gene for dominance?
786504
I think it's a particular American prejudice. People in the UK sometimes marry their cousins. It has never been seen as a problem here.\n\nPersonally I was surprised to see the furore among the American contingent!\n\nHere's a link to an American article which confirms that there are no real genetic grounds for forbidding cousins to marry.
201401
A few reasons...one is because, statisticaly, random flucuations are more likely in a small population, kind of like if you flip a coin twice, you might get 2 heads or 2 tails, but if you flip a coin 100 times, you'll probaly get something close to 50-50. \n\nAnother is that rare genetic types are easily 'diluted' in a large population, but can become significant in a small population. Think about why family members shouldn't marry: most of us have some harmful recessive genes, but it's unlikely that our spouse will have the same one, so it's not a problem. But, if we marry within our family, there's a much greater chance that our spouse also carries the recessive gene.  In small populations, more recessive traits will be expressed.\n\nFinally, a small popluation is usually isolated from the larger one, so it might be exposed to specific environmental conditions that force adaptation or create some selective pressure. One famous example of this is Darwin's finches, on the Galapagos islands: because each island has specific types of plants, each island's population of birds was under pressure to adopt to eat those plants, and they each ended up with a beak taylored to their own island's seeds.
381802
None, without diversity we would literally die. Our gene poll couldn't do it if we were breeding among the same "clans" or groups for hundreds of years, we would all have birth defects.\n\nWhy would people travel to other Countries? Is it for visiting and learning about other Cultures and their surroundings / habitats?
507695
Heredity. You got the genes for that trait from your ancestors.
35201
Most anthropologists believe "race" is not a meaningful concept.  Skin color mutates and alters rpadily as people move around.  It makes more sense to speak of ethnicity or culture than race.  And from a biological sense, when genes in humans do vary, it is usually due to geography and previaling conditions.  For example, most adult humans are lactose intolerant, but both pale northern Europeans and dark Masai folk can digest lactose.  That's because both groups were into dairying.
268676
There are actually duplicate genes for every function. You received one from your mother and one from your father. If one is missing or defective, the other takes over. Sometimes both are required and you would express a recessive trait. If the gene is crucial, your life is shortened or aborted.  Some conditions have an entire chromosome missing (Turners syndrome) without catestrophic effects.
250276
It is most definetly a recessive gfene. I know this because so few people posses this trait. However there is a possibility of it occuring. Actually the small big toe depends not just on one allele but several alleles at several loci but in the end all sucha lleles are recessive and do not give heterozygote advantage