The racial melting pot of humanity

[Anonymous]

Today's BBC article regarding the date at which native Americans first reached said continent, has got me thinking.

Apparently, genetic evidence indicates that the earliest they could have arrived was 15,000-18,000 years ago. Meanwhile, Europeans were spawned from the same ethnic origins: Asians living 50,000 or so years ago.

When you can measure the time taken for new races to appear across so small a period, it not only highlights the preposterousness of racism, but shows that we are surely bound to end up as one homogenous race in a very short space of time. Given that we don't have to move through continents as hunter gatherers over many generations, but can travel and "interbreed" with impunity, how long can it be before there is, once again, only one racial variant of human being?

One thousand years? Two hundred years?

I mean, how many generations is 15,000 years: about 600? Just 600 generations back, and American Indians were racially the same as the Asians of the day.

Spinny.....

 

[phgnome]

I've had this exact same thought recently -- that we might go through genetic convergence. The setting seems right for it. I can imagine it happening almost fully in 500 years.

I already kind of see it -- there are so many people with mixed backgrounds where there is no distinct ethnicity: black hair, brown eyes, light to olive complexioned. However, with time, the skin colour may get slightly darker to light brown.

I think it's a good thing -- it'll give people immunity to ethnicity-related diseases (i.e. sickle cell anemia, malaria, etc.).

I think I heard a theory somewhere that an ice age caused the genetic divergence in the first place.

The divergence reminds me of some biblical story I heard on the radio one time -- about the tower of Babel falling and how no one understood each other after the tower fell.

 

[Anonymous]

Well, there are two things to consider here; one is that geneticists seem to have a problem with the concept of race as such, and any so-called racial group will have nearly as much genetic diversity within itself as the rest of humanity; there are genetic markers, which can show where a persons ancestors probably came from, but the amount of mixing is so high that you have to approach these things statistically.

We all contain a swarm of genes, which cling together like bees, but mingle when a new individual is concieved;

and there are genes in this swarm from every one of our ancestors; howcan a swarm be compatible with the concept of race? I have 'black' genes in my genome, as most people do; most 'black' people have 'white' genes and so on.
How can the concept of race be valid when you consider the behavior of individual genes?
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However, the melting pot is not necessarily the only future. Some countries are becoming more isolated, rather than less;

China for instance has a sixth of the world population,and shows no sign at the moment of integrating.

So whatever characterises the swarm of genes inside the Chinese population might continue into the future, and perhaps even forward to the stars thanks to their space program, without becoming mixed with the rest of humanity to any great extent.

 

[Anonymous]

I've often wondered how many generations an African race would need to live in Nordic lands before evolution lightened his skin (ruling out breeding with paler people)
And vice versa for white people living in hotter climes.

In the South of France I met many people with brown hair, olive skin and pale blue or green eyes. To all intents and purposes they had "white" features. One of these ladies was Algerian so basically she was African.

I have a friend with straight blonde hair, blue eyes and pale skin. At school she was teased, called the "Blonde N*****" because she has the facial features of a black person, even though none of her family have an idea of their heritage.
Jade Goody from Big Brother had a white mother and a black father. She inherited his generous mouth but in all other respects, is a white blonde. Black genes are supposed to be more dominant but it doesn't always work out that way.

My father, who has Irish ancestry, has black eyes and brown hair. I have blonde hair and brown eyes, one brother is brown hair and green eyes and the other is mousy hair and blue eyes.

There's a DNA test being offered, to discover where your mother's ancestors came from. They can pinpoint certain areas in Europe which to me seems silly because it's all a matter of how far back one chooses to delve. Ultimately, we're all Africans.

In the USA, which has a greater racial mix, there are some interesting and frankly breathtaking people around. Vanessa Williams, a black girl with blue eyes, is to me one of the most beautiful women I've ever seen. Having brown eyes myself, I see them as rather unattractive and plain! I work with a Filipino woman who has an English husband. Their daughter has brown hair, with pale grey eyes ringed in black.
If and when the racial melting pot standardises our colour, it will a twin edged sword. Racism will virtually end but so will the diversity that makes us beautiful to some, ugly, interesting or strange to others. I think I'm glad I won't be around to see it.

 

[MrRING]

I've often wondered how many generations an African race would need to live in Nordic lands before evolution lightened his skin (ruling out breeding with paler people)
And vice versa for white people living in hotter climes.

The way I understand it, something would have to be chosen for on an evolutionary level before any change would occur.

For a change to happen, it would mean that a mutant gene (either a lighter or darker skin tone) would have to exist that when mixed with climatic conditions would have to be favorible for one skin tone to be able to have children and the other skin tone to have no chance (or a lessened chance) to breed. If the change doesn't affect the ability to have children, then there is no evolution.

For humans, skin color can be dealt with in the extremes they weren't meant for by sunscreen or vitamins or clothing, so there aren't any choices being made.

In modern times (assuming adequate access to resources and limiting human sexual interaction within their own group), the dark skinned groups in the arctic and the light skinned groups in the tropical climate would have no changes from their ancestors.

At least as I understand it.

 

[MrSnowman]

I've often wondered how many generations an African race would need to live in Nordic lands before evolution lightened his skin (ruling out breeding with paler people)
And vice versa for white people living in hotter climes.

If you took a bunch of Saharan nomads and made them live at the North Pole for a thousand years, they'd stay the same colour, and vice versa for any (Caucasian ) Eskimos who you sent to live in the desert. Evolution doesn't work like that. The environment cannot directly affect our genes, it can only promote the spread of particular ones, if the effects of those genes make it easier to exist within that given environment. Look at Giraffes.

What I've always wondered about over the years is the mechanism by which the different races emerged. I suppose the fact that there are 3 distinct racial groups on Earth could allow for two spontaneous mutations from black people sometime long ago, but it doesn't explain the dispersal patterns of humanity or anything. Ar.. my brain hurts.

 

[phgnome]

However, the melting pot is not necessarily the only future. Some countries are becoming more isolated, rather than less;

China for instance has a sixth of the world population,and shows no sign at the moment of integrating.

So whatever characterises the swarm of genes inside the Chinese population might continue into the future, and perhaps even forward to the stars thanks to their space program, without becoming mixed with the rest of humanity to any great extent.

There's a whole lot of Asians that are mixed with different ethnicities. There is a whole sub-culture of media devoted to the half-Asian mix. The growing explosion is the result of wars and immigration policies of receiving countries -- cultures have a tendancy to mix during a war, producing bi-ethnic offspring.

Whether the grounds upon which these multi-ethnic offspring were conceived is ethical or not is another matter. Some women in the Asian countries during wars worked in the sex trade. Some conceived children as a result of rape, while others entered into relationships foreigners in their homeland. People in war-ridden countries also flee to other countries (like many people in Iraq are doing right now) and they or their children may marry a native of the country that they emmigrated to.

The bi-ethnic offspring may also choose a mate of a different ethnic background. The more fighting there is (and I imagine there's a lot more than there were 1,000 years ago), the rate of ethnic convergence would accelerate.

What I can't imagine yet is how the ethnic divergence occurred -- what the conditions could have been. Perhaps climate and/or camoflage and/or habitats (i.e. caves in the north -- where you would need to see well in the dark and have lighter eyes?).

 

[MrRING]

I think skin tone may have a dual purpose - light skin reacts well to the amount and kind of light generated in the north, which is good to prevent cancer AND get the appropriate benifit from solar radiation without getting cancer. Dark skin works to block the light in equatorial regions, blocking for cancer better with incresed solar radiation and still allowing the right about of solar radiation benifits to work.

Say you are a dark-skined primitive human. When you move up north, where there is less sun and heat and you are wearing more clothes, you will likely get much less exposure to direct sun rays and will be missing vital nutrients. If you have a mutant offspring who is very light, they will have an advantage in the new climate and will have more opportunities to breed with the tribe.

Or on a lesser scale, you have 7 kids, and there is two who are more light... just that difference may make them work better in the climate, have more child-producing opportunities, and thus preserve the lighter genetic inheritence to their offspring, who will in turn have children with other lighter individuals.

As far as the advent of the eliptical lid that creates the Asian eye, for some reason I want to say that was an adaption to cold but I don't remember what was said in my college anthropology class to be sure.

 

[MrSnowman]

Hmm.. from what I understood though, there's no disadvantage to having dark skin in a cold climate. In fact, it's an advantage in a way, as the darker skin would be more absorbant than lighter skin where there's less sunlight available. I'm of a mind that it was just a spontaneous mutation at some point. I can kind of see it now.. the 'light skins' being outcast, and then going off to multiply somewhere else. But then you get things like eye and hair colour. Brown eyes being a dominant gene and everything, it's highly unlikely that you'd get light skin AND blue eyes in one generational mutation. I suppose until we get time machines, we'll never know

I did have an old US trashy sci-fi comic once, that had a story where dark skinned people were the indigenous Earth population, white people were the descendents of alien invaders who were defeated by OTHER aliens, these other aliens being of an oriental-type race, whose eyes were as such because they were from a planet very close to a sun, and they had to squint because it was so bright all the time!

Take your pick, evolution, or alien invaders! :blah:

 

[MrRING]

Hmm.. from what I understood though, there's no disadvantage to having dark skin in a cold climate. In fact, it's an advantage in a way, as the darker skin would be more absorbant than lighter skin where there's less sunlight available.

From what I understand (is there an anthropologist in the house?) is that the skin gets certain benifits, be it creating vitamins or deriving some kind of healthy benifit, from regular sun exposure. Light skin gets the right amount of light higher on the globe, but in equatorial regions the skins burns more, leading to more instances of melonoma. The solution? Clothes and sunscreen.

Darker skin can be exposed more to the suns rays before burning. In a more northern climate that very level of protection that works well in a tropical climate will mean that they get less of that benefit from sunlight than a lighter skinned person, because their skin repells more of the radiation.

I think there was a story on Yahoo within the past few years that backs this up, but it basically said that darker skinned people living in the frozen north should take more vitamins or such - it's not something that's really going to have much of an effect on modern humans, but would have a big effect on early hunter/gatherer societies.

 

[MrSnowman]

Yes, I see what you mean now. Darker skin does have a much higher melatonin level.. that's why it's darker! And the more melatonin in the skin, the more efficient it is at absorbing (not repelling) UV rays.

But if you look beyond skin colour, at the typical racial features of the three main racial groups, it's something than climate change alone cannot account for. I quite like the multiregional evolution idea, where different varieties of early humans came out of Africa at different periods over the millennia, so white people could be descended from say Baboons, Orientals from Chimpanzees (or their equivalent ancient primate type) etc. I know it doesn't hold with the idea of this 'Eve' being, but it would certainly account for the greater genetic diversity amongst humanity, rather than relying on one particular group which somehow spawned all these weird and wonderful variations.

If we all did come from different sources, then it'd make more sense for humanity to aim for some sort of racial amalgamation, in order for us to reach our true potential, sort of like breeding a new kind of pedigree cat out of some very different types of non-pedigree toms and tabbies.

 

[MrRING]

I think the thing that shows we all have the same ancestor is mitocondrial DNA, which indicates all modern humans share the same ancestor.

Here is the conclusions drwan on this page: http://www.actionbioscience.org/evolution/ingman.html

Population genomics

The robust phylogenetic tree reconstructed with this dataset of complete mitochondrial genomes gives strong support to the 'recent African origin' theory. By determining the substitution rate of the genomic sequences, it is possible to derive dates for points on the tree and build a chronology of events in the evolution and migration of our species.
The most important date, in relation to the competing evolutionary theories, is the time when all the sequences coalesce into one -- the 'mitochondrial Eve.'
From this study, a date of 171,500 years ago was obtained which fits remarkably well with that proposed in the recent African origin hypothesis.
For us to accept multi-regionality, we would expect a much older date, as it would represent the common ancestor of Homo erectus rather than of Homo sapiens.

The evolutionary history of aboriginal populations still remains a mystery. This study is only the first and population genomics is in its infancy. The future will provide more studies with ever-increasing numbers of sequences from yet unanalysed populations and perhaps an interface between genetic data from different loci. For example, a recent study of ancient human remains in Australia integrated genetic data with the information collected by physical anthropology. There are many important questions that remain to be resolved such as how and when the Aborigines arrived in Australia and the evolutionary history and relationships of North and South American Indians.

 

[MrSnowman]

Ah, I forgot about those cheeky mitochondria! You know, I came up with an idea a while back that SHC was all down to mitochondira; i.e. that all it takes is a few molecules of mitochondrial adenosine triphosphate to spontaeneously go *poof* and it would cause a localised chain reacion that would render a good proportion of the human body as dust. No-one listened though

Back on the race subject, however, maybe mito.. dating does show that that we all came from one female ancestor (mito.. DNA being the only unsullied part of ourselves that is passed on, of course (unsullied you ask? Well, if mito DNA was to degrade, basically, human mito.. would degrade over generations, and we rely on mito.. to provide us with energy. Carbos + Mito = life. (just a note to the unitiated.. just google ATP and mitochondria))), but there's always the chance that the dates are a little wrong. Carbon dating is not an infallible process, and I've yet to see any concrete evidence that detracts from the multiregional evoltuion idea, whereby it's possible that Eve existed MUCH earlier than 150k years ago, say 300-400k, and various primate races emerged from her offspring, , spreading their wings at various periods, thus lending a greater possibility to the spontaeneous mutations which *must* have ocurred at some point to get what we have today.

It all depends, I suppose, whether one subscribes to Lamarckism or Mendelism. Can a cold climate make darker people lighter, or is it just down to natural selection whereby those of a lighter skin survive in a climtate which has a propensity to be a bit snowier a little better because their predators can't spot them? Who knows?

I am drunk, and I leave the conversation as such

 

[stu neville]

I think the thing that shows we all have the same ancestor is mitocondrial DNA, which indicates all modern humans share the same ancestor.

All evolution seems to have a fractal quality to it: all primates are descended from one small shrew-like creature, which then split into lemurs and monkeys, lemurs split into lemurs, aye-ayes and possibly flying foxes, monkeys became monkeys and apes, apes became chimps, gorillas, orangs, gigantopithecii and the human root, which in turn became neanderthals, ourselves and half a dozen other species. In each case, it would have been one mutated gene that triggered the split: in effect a sport becomes the norm as it has some form of subtle advantage relating to it's environment, which becomes more pronounced with successive generations - so yes, it's actually probable that was an "Eve", a single female proto-human from whom we are all descended. Which for someone who takes the Bible with a pillar of salt is a little disconcerting, I might add.

In fact, if archaeologists in Central Africa discover Eden, or as I posited last year the remains of Noah's ark, then I'll happily eat my hat and return to Sunday school forthwith .