Naked Science Forum
Life Sciences => Physiology & Medicine => Topic started by: Europan Ocean on 06/03/2013 15:13:35
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There is a fellow on youtube who suggests there are great differences in DNA between the races of people. In fact saying that we are mixed with aliens to make such differences!
As I understand it, we are different in phenotype while our genotypes are very remarkably similar! Is it 99.9 percent in common? Pointing instead to people coming all from one small tribe thousands of years ago. A tribe considered to come out of Africa.
I look at Orangutans and they look so similar to eachother. But are said to be more genetically diverse than us. And we have is it 97 percent DNA in common with them?
I am looking through Wikipedia for ideas and wanted to ask the members of the naked scientists forums and the staff. Could I have an opinion or two?
Why do we look so different, one from another?
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I don't think we humans do look very different from one another.
We just get very good from a young age at observing the very small differences between each other (like: "this is my mother" and "that is not my mother").
Natural things like hair colour, skin tone, scent and gait can help.
Non-natural things like hair styling/colouring, cosmetics, perfumes, clothes, motor vehicle colour, mobile phone and context may also help to identify each other in an increasingly crowded world.
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There are specific areas of the brain devoted to facial recognition and damage to this area can result in a person not being able to identify or recognize faces, even ones they used to know. (It is not simply a memory problem like Alzheimers.)
Another interesting aspect of facial recognition is that if people are not exposed to many faces of particular ethnic groups during infancy and early childhood, they have much more difficulty recognizing those kinds of faces later in life. The "they all look alike to me" phenomenon is not necessarily the result of racism.
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As to why humans look different, most of those differences have to do with the fact that unlike most animals, humans migrated all over the planet to different climates. Melanin protected the skin of people living near the equator. Being tall and lean, or short and stocky, may be related to temperature, energy conservation, and whether food was abundant or scarce. The amount or type of body hair, shapes of noses may also be related to climate.
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We are actually rubbish at recognising faces that aren't familiar to us - all it takes is a change of lighting, hairstyle, expression or view and we cant recognise one stranger from another. People have had credit card payments refused because they don't look like the person in the picture due to differing hairstyles or views or have cards accepted because the person in the picture is vaguely like the person (Kemp et al 1997). Its also why police line-ups are so fraught with difficulties- (Wells & Olson 2001, Anastasi & Rhodes 2006) - "they all look alike to me" isn't specific to other races, it applies to all strangers.
This guy also has some interesting ideas on humans as a species:
http://www.ted.com/talks/juan_enriquez_will_our_kids_be_a_different_species.html
Of course there is also another view on the definition of aliens. There is a view that anything that is contained within our own universe is not alien to us - we all came from the same stuff, are made of the same building blocks etc etc.. So there is an argument for saying that a true alien has to come from another universe.....but that's another story.
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Considering that even a chimp and human cannot produce offspring, how did this alien DNA become combined with ours? (Sorry I don't have the bandwidth for videos at home, so I didn't watch it.)
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The Ted talk doesn't refer to alien DNA in humans.
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This is an example video of pseudoscience and the theme of aliens soon coming. And could become as dangerous as solar temple.
Below, video one, at about 2 minutes in mentions humanoids...