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180k-Year-Old Mutation Allowed Humans To Become Vegetarians, Move Out of Africa
An anonymous reader writes "Early humans were able to move from Africa after a single genetic mutation allowed them to become vegetarians, scientists claim. The switch, which allowed humans to process vegetables, meant that humans were able to move away from water sources and spread across the continent. A team of geneticists compared DNA sequences from a variety of people around the world to see how different populations relate to one another and when they have gone their separate ways. The scientists found that a key genetic variant gave humans the ability to convert fats from plants into essential nutrients for the brain."
We were already omnivores, this allowed us to not be required to eat certain foods (fish and shellfish), so we could survive away from the sources for those.
The scientists found that a key genetic variant gave humans the ability to convert fats from plants into essential nutrients for the brain."
To this?
180k-Year-Old Mutation Allowed Humans To Become Vegetarians, Move Out of Africa
People who don't know their scientific terms mis-quote scientific articles. News at 10.
We'll go in order...
mutations are so rarely beneficial
The vast majority of the mutations that are widespread through the population are either benign or beneficial. The ones that aren't don't stick around in the gene pool long enough to become widespread. It's the other half of the selection pressure you mentioned: The selection pressure culls bad mutations out quickly, so the good (or at least ineffective ones) are all that's left. This is definitely a case of history being written by the victors: The bad mutations don't usually stick around long enough to be noticed (in long-term history).
So how do they know it was a mutation?
Because some folks have it, and other folks don't. From the geographic distribution of where the haves and have-nots are, combined with the prevailing theories about human movements, the researchers can estimate what genetic group first got the change.
one mutated birth isn't going to suddenly diffuse across an entire species.
It doesn't happen suddenly. That one mutation spreads through one family, who suddenly has the ability to survive without eating fish (substituting vegetables, instead). Over the next thousand years or so, that family (and the associated mutation) spread across the local region, and the knowledge of "it's okay to eat vegetables" spread with it. Since that group could wander further (carrying longer-lasting vegetables rather than fish), they spread farther than other groups, until they eventually became dominant.
How one random gene in one birth suddenly afflicts an entire population?
Just to be clear, it doesn't. The one random change will be in one family line, and only really become widespread if it allows the family to outgrow the rest of the population, or if the the rest of the population dies off.
You do not have a moral or legal right to do absolutely anything you want.
The Slashdot headline is wrong and the initial website it links to has a wrong headline.
If you read the scientific paper, it says the mutation happened about 85,000 years ago, not 180,000 years ago. This makes it logically consistent with other biological discoveries, archaeological finds etc.
Basically, I don't understand this article.
The problem isn't the article. It's your limited understanding of evolution and genetics. :-)
According to modern evolutionary theory, mutations create ALL change. Most mutations don't do something favourable, or really actually probably don't do anything at all, but some of them are favourable and those individuals go onto spread that gene more effectively than their peers until many many generations later, this gene has spread throughout the species (or the region, or the tribe, etc).
If a tribe of ancient humans gradually gained the ability to survive without meat, and a major event such as volcanic eruption or something killed off the local food staple, the tribe that could survive for years without meat might be the only survivors in the entire area. If the species is isolate to that area, they could plausibly be the only survivors of the species.
In this way it is actually possible for the entire species to gain a trait in just a few generations. Or, a mutation can gradually make its way into cultures in a more limited sense.
For example, genetic analysis suggests that ALL blue eyed individuals are descendants from a single individual with a unique mutation about 6-10,000 years ago. People with brown eyes have a huge variety of genes that affect pigmentation, whereas all individuals with blue eyes have a very specific sequence that controls it, which, along with mitochondrial DNA surveys, leads researchers to conclude the bit about a single individual.
Pretty cool, eh?