Saturday, March 15, 2008

Only 99.5% similar.

The journey of mankind spanning 150000 years. (via).

So, we all originated from one place, kept multiplying and moving from place to place. So, that should make us all genetically quite similar, right?

Mark Bagel, evolutionary biologist, says we could differ more than we thought. Modern genomic studies reveal a surprising, compelling and different picture of human genetic diversity. We are on average only about 99.5% similar to each other genetically. This is a new figure, down from the previous estimate of 99.9%.

Isn’t 99.5% good enough? Why is this Bagel being so finicky about a mere 0.5%? To put what may seem like miniscule differences in perspective, he says we are somewhere around 98.5% similar, maybe more, to chimpanzees, our nearest evolutionary relatives. Modern humans spread out of Africa only within the last 60-70,000 years, little more than the blink of an eye when stacked against the 6 million or so years that separate us from our Great Ape ancestors
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Bagel says that the new figure for us, then, is significant. It derives from among other things, many small genetic differences that have emerged from studies that compare human populations. Some confer the ability among adults to digest milk, others to withstand equatorial sun, others yet confer differences in body shape or size, resistance to particular diseases, tolerance to hot or cold, how many offspring a female might eventually produce, and even the production of endorphins — those internal opiate-like compounds. We also differ by surprising amounts in the numbers of copies of some genes we have.

He concludes, “What this all means is that, like it or not, there may be many genetic differences among human populations — including differences that may even correspond to old categories of 'race' — that are real differences in the sense of making one group better than another at responding to some particular environmental problem.”

I am not sure if Bagel is right when he says that we are more different than we had thought, but I am more than convinced that we remain much closer to chimpanzees than we would like to believe.

6 comments:

Brain Drain said...

Raj,

What always surprised me is the fact that we took less than 60000 years to develop these resistances to many of the natural inhibitors ( like temperature, terrain etc). Moving out of Central Africa to all parts of the world, we are already changed a lot internally and externally ( colour of body , the heights, the hair, the structure etc). We are in effect questioning this by the new found migratory impulses of human. It doesn't fit in the scheme of evolution.

Jayan

Raj said...

Jayan,I guess what Bagel is trying to say is that, it is futile to believe that 'we are all one'. Far better to recognise that we have all evolved in different ways and are we can never be the same everywhere. And then to find an acceptable way to co-exist, with all the differences.

Jayan said...

I understand that point. I was adding to the same as "are we doing a counter evolution" . This is ain interesting subject and not "boring stuff".

Raj said...

Thanks, Jayan, I see your point.

About the 'boring stuff' tag, I am trying to oblige a friend who said that he visits my blog only to read humorous stuff. he wants to be alerted if I attempt anything remotely serious.

Vijay said...

We are different in a lot of ways. And based on our location, each of us have evolved along a different path since migrating out of Africa.

We're going to evolve more and a thousand years from now, the gap might be even wider.

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