Tanner The Monotone:
Tanner The Monotone:
Socially and in the short term (my life time), I'm for them
Genetically, in the long run, I would be against them. If we don't want one type of human race, then we need to have some kind of selective breeding in the far future.
Why exactly should we care if races go away due to interracial marriages?
There would be trouble with genetic diseases like sickle cell. Plus there might be problems with birth defects.
Though, theses might be moot points, because by the time this happens we will probably be able to mess with our genetic code like it's plastic surgery.
This is actually the opposite of what would happen.
Population separation creates diversity between populations, but reduces diversity within populations. The vast majority of genetic diseases are recessive, requiring either heterozygous or affected-homozygous parens that both carry the defective allele and pass it on. In small populations the rate at which an allele goes to fixation through either Genetic Drift, the Island Effect, or Genetic Draft is multiple orders of magnitudes faster than with larger populations.
Two forces work to counter-act the homogeneity of genotypes in populations; mutations and immigration/emigration. Immigration counteracts fixation of deleterious alleles by simply injecting more alleles into the population, creating more heterozygosity. It doesn't actually take that much to maintain heterozygosity in a small-to-moderate population; just a few people immigrating per year.
Mutations are the random component of evolution and also counter-act fixation by changing alleles according to mechanisms which operate on pure chance. Natural Selection then acts on the new mutations and either deems them neutral, better, or worse. In the case of the latter, it's usually swept from the population quickly if it's significantly worse since the individuals the mutation occurred in do not reproduce.
The benefit of reducing heterozygosity between populations (done via immigration and emigration) - bringing the two populations closer, genetically speaking - is that it takes longer for the mechanisms which reduce genetic diversity (Draft/Drift/Selection) to act. The larger the number of interbreeding individuals (the population), the longer they will retain heterozygosity, and the less susceptible the population as a whole will be to deleterious mutations and they will be better able to adapt to unknown challenges placed on them by Selection since there's a wider variety of alleles (any of which could prove beneficial).
Sickle Cell Anemia - the specific condition you mention - is actually positively selected for in areas with high concentrations of mosquitoes and parasites. Heterozygotes for Sickle Cell have a significantly reduced chance of contracting Plasmodium vivax (Malaria) due to the way which the pathogen operates. Sickle Cell homozygotes are usually fatal very early on, so they do not reproduce. Therefor a person who has Sickle Cell Anemia and is capable of reproducing is almost always a Heterozygote, and unless they have sex with another Heterozygote (which is exceedingly rare in any population besides those in Africa - since we're talking about Interracial marriages here), the children would be - at worst - heterozygotes as well, with a pretty good chance of not carrying the allele at all.
Interracial marriages make very, very good evolutionary 'sense.' The more alleles there are in a species, the more obstacles that species can overcome. Humans, right now, aren't very diverse. A major bottlenecking event 30k-40k years ago reduced the Human population down to a few thousand, significantly reducing our diversity. Thanks to massive population explosion in the last hundred or so years, diversity is returning again.
This is, of course, assuming you prescribe to view the Human race as various "races" instead. The taxonomical definition of "race" is a species which contains phenotypically different individuals that can still interbreed and produce viable offspring. However, the usefulness of the term has been debated among taxonomists for decades. Modern genetic techniques and biochemical understanding all but eliminates the necessity - particularly since "race" can be incredibly misleading.
Vitiligo is a dermological condition where the melanocytes (which everybody has the same # of regardless of 'race') simply reduce their melanin production. The result is a very slow, but inevitable change from "black" to "caucasian":
If you were to categorize her based on "race" alone, you'd say she changed "race" somewhere in 4th or 5th grade. Because it's not a change in genotype - merely a change in phenotype - the term "race" here is completely useless.
In addition; because skin color isn't Mendelian and has several levels of Dominance, the children of interracial couples can literally be any color. The entire spectrum of humanity can be produced. More so, as long as there's ANY interracial history in your family within the last 4 to 6 generations, your kids could have an entirely different race from you if you meet up with another person with similar genetic history.
So, yes, technically Humans do have varying "races" - but you're also using a word that's been eclipsed by better understanding and mountains of knowledge to back up that understanding.
If you want even more proof that interracial marriage is a good thing, consider these (scientifically approved) ponderings:
-Women near their menstruation will prefer the smell (and phenotypic features) of men who do NOT share Major Histocompatibility Complex (also called MHC or HLA) alleles (the alleles which define the adaptability of your immune system) in order to produce offspring with more novel MHC alleles who will probably be better capable of dealing with current pathogens. It's hard to get more opposing MHC alleles than going interracial.
-Women who are perceived to be more attractive than their male counterparts often describe themselves as "happier" in their marriage than those who consider themselves 'as' attractive or 'less' attractive. This is NOT to say that interracial women are more always attractive, but rather that the different ideologies governing attraction between ethnic groups may have a positive affect on happiness inside a relationship since attraction can significantly impact happiness while inside a marriage (though there's no study to confirm this).
I think I've said my piece. Full disclosure: I actually dig black/mixed/Latina chicks a lot more than I dig white chicks (and I'm Scottish/Russian). No, it's not a fetish. I don't idealize stereotypes concerning black women or mixed women. I simply find them more attractive for reasons I can't fully explain.