Son of Odin

Before I ask my question, I want you to know that I am not a racist, but I am really curious about this, and everywhere, where you discuss something like this, it is considered taboo, and not to be discussed. Maybe here it will be different.

If I understand evolution (which I'm not sure of, so correct me if I'm wrong), mankind evolved from a common ancestor into his current form. That means that at some point (due to isolation of groups in different external conditions) people in africa evolved different from people in europ (for example), thus explaining skin color, hair-type,...differences.
Now...is it in the interest of mankind to "crossbreed" the human races, or is it better to keep them seperated ?
With dogs, I know that if you breed them to "sharp" they are weak and prone to deceases, and "bastards" are much stronger and resistant to dicease. But, in general, bastard dogs are ugly, and they differ greatly from one another (even in the same nest). But, does that have anything to do with evolution at all ?
So, in the interest of the human race, would we do better to crossbreed or to stick with our own kind ?

SEF

1. You're not going to be able to dictate to everyone what they do even if one or other choice were in their best interests. If things worked that way among humans no-one would be a smoker.

2. A mixture of both is probably best. Isolation allows re-inforcement of any interesting characteristics which arise and gives the opportunity to see whether they are useful for anything. Mixing back up allows other populations to share the useful characteristics. There's an Italian lineage which has randomly acquired resistance to heart disease. If they hadn't been isolated in one area people would never have noticed. Now, however, everyone probably wants to be their relative! The same thing may be about to happen with AIDS resistance.

Ergaster

Humans in Europe are simply northern variations of humans from Africa. That is, humans from Africa migrated out of Africa and populated the earth. At least twice: When Homo erectus left Africa sometime very close to 2 million years ago and ended up pretty much everywhere (though the entry into Europe was rather late, well after 500,000 years ago), and then again maybe 40,000 years ago when modern Homo sapiens entered Europe (and everywhere else) from Africa and displaced the existing archaic populations--though I hasten to note that there exists controversy over the second migration. A not-inconsiderable number of paleoanthropologists believe that modern humans evolved from the already-existing populations all over the world.

At any rate, there are a few geographically-based phenotypic differences among humans, but they are biologically exceedingly minor and the boundaries are extrememly fuzzy, if they even exist at all. In other words, there really wasn't all that much isolation.

"Our own" is the entire human race--we are all Homo sapiens, we simply do not differ from each other to any significant degree, and whether or not we should stick to "our own" is a meaningless biological question. Humans have never "stuck to their own" anyway, so it's also moot (i.e. even if you could manage to identify a "race" in some sort of meaningful way, there are no pure races anywhere on earth).

Mixing "races" is a social question, not a biological one. Besides--it's a social experiment that we've already tried (look up Eugenics) and I doubt any reasonable person wants to repeat the experience....

Doubting Didymus

I imagine that the best evolutionary strategy if we wanted (for some reason) to improve our collective genetics, would be to breed as widely and as often as possible regardless of race, ensuring the greatest number of beneficial recombinations.

Of course, a high death rate from a wide variety of causes would also be "desirable".

I must say that 'improving our genetics' is a questionable goal, but if we're dealing in hypotheticals, I can't think of any advantages of keeping breeding within races.

mrmoderate

I think the key point here is that all humans are the same biologically. Different races are more a social aspect than a biological one. Races are not breeds like animals are. (Although it is believed that all domestic dogs come from an origninal wolf stock, so maybe there is some similarity.)

The fact that human races are compatible for breeding is a good sign that they are in fact meant to be able to breed. A human cannot successfully breed with a dog or sheep or goat for example.

Doubting Didymus

This is so, but there are a few localised beneficial mutations sitting in human populations out there that widespread interbreeding would spread.

But, on the other hand, you also have slightly more complicated genetic situations like the well known sickle cell anemia / malari protection situation. Spreading that one around might be more harm than good for populations that don't have to deal with malaria.

I guess genetics is too complicated for a simple answer to 'who should we breed with' to ever work. We're best off going at it in the traditional way, I reckon, although that was never seriously in question to start with.

DinoStoned

Cross-breeding for phenotypic purposes would probably be easy to pull off, but it is impractical to cross-breed to isolate beneficial genetic factors, or wipe out genetic disorders from our gene pool.
It'd be a very tedious job, as we don't breed like rabbits or bacteria, and we do not have a long-lived outside observer not of our own species (and thus has little emotional attachment to us) to monitor our progress and ensure that nothing goes wrong with the 'project'.

mrmoderate

I am told by friends who are of an interracial marriage that their children are immune to sickle cell because of the genetic mixture. Are they wrong in their belief?

SEF

That isn't something to which one is immune. Sickle cell anaemia is the result of a mutation which confers a benefit against malaria but offset with the disadvantage of excruciating pain from time to time and slightly shortened life expectancy. A double dose of the mutation is fatal at a fairly young age. So your friends and their children either have the mutation or they don't. Even possessing it doesn't make one completely immune to malaria - it just prevents the infection from being very successful.

rlogan

Please send Stacey Dash to my door so that my progeny may share the useful characteristics.

Thank you.