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genetic data

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According to an international team of scientists, the origins of human tuberculosis have been traced back to hunter-gatherer groups in Africa 70,000 years ago.

The research goes against common belief that TB originated in animals only 10,000 years ago and spread to humans.

The work, published in Nature Genetics, outlines the strong relationship between the evolutionary history of both humans and TB.

The disease causes more than one million deaths every year.

Previous research has indicated that human TB originated about 10,000 years ago in Africa during the Neolithic Demographic Transition (NDT), when the human population was expanding and agriculture was becoming prominent.

Researchers combined geographic and genetic data from 259 strains of TB to reconstruct its evolutionary history and compare it to the origins of humans in Africa.

The origins of human tuberculosis have been traced back to hunter-gatherer groups in Africa 70,000 years ago

The origins of human tuberculosis have been traced back to hunter-gatherer groups in Africa 70,000 years ago

Prof. Sebastian Gagneux, from the Swiss Tropical and Public Health Institute, said: “We found that the most basal – the earliest – lineages of TB and humans originated in the same place, in Africa, 60,000 years earlier than what people previously thought.

“What we have done is provide a strong hypothesis to reinforce the idea that TB originally started in humans, and migrated to animals during NDT.”

The question the scientists are now trying to answer how TB managed to survive 60,000 years among small groups of people.

A striking feature of TB, which is not common in other diseases, is that people can be infected with it for years before showing any symptoms. The disease is able to reactivate itself after a certain time period.

This latency is what the researchers suggest kept TB alive during early years.

Prof. Sebastian Gagneux said: “If there are only a few people to infect, it makes no sense to kill them, as you would risk killing itself too. It’s an evolutionary dead-end.”

Once the human population started expanding during the NDT, TB became more active and was able to spread farther.

So, as the number of hosts increased during and after the NDT, so did TB’s drive for increased virulence.

“The next step in this research would be to use genetic information to understand this activation and deactivation mechanism of TB,” said Dr. Inaka Comas, lead author of the research.

TB remains a global threat, causing 1.4 million deaths in 2011, according to the World Health Organization. If scientists can understand how TB and humans co-developed, it may help find a way to reduce its prominence.

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British scientists identified 24 genes containing information that could lead to a drug to stop many children becoming short-sighted.

The discovery could spare families from spending a fortune on contact lenses, as well as the expense of laser surgery.

More importantly, the discovery would mean future generations would no longer be at risk of developing complications of short-sightedness that can lead to blindness in later life.

Short-sightedness is becoming more common as we spend more time indoors and in front of TV and computer screens.

Caused by overgrowth of the eyeball, it usually starts developing in childhood, and in severe cases can lead to macular degeneration and other forms of blindness.

The fact that the condition runs in families means that genes are involved.

Almost three years ago, the first gene that causes short-sightedness was identified by King’s College London researcher Chris Hammond.

Now, leading an international team of scientists and trawling through genetic data from 45,000 people from around the world, including the UK, he has found many more.

Prof. Chris Hammond said: “This study reveals for the first time a group of genes involved with myopia and that carriers of some of the genes have a ten-fold increased risk of developing the condition.”

British scientists identified 24 genes containing information that could lead to a drug to stop many children becoming short-sighted

British scientists identified 24 genes containing information that could lead to a drug to stop many children becoming short-sighted

Working out what the genes do and what goes wrong in short-sightedness could lead to eye drops or other drugs to treat the condition.

Prof Chris Hammond, whose research is detailed in the journal Nature Genetics, said: “Now we understand more about the genetic triggers for the condition, we can begin to explore other ways to prevent progression.

“It is an extremely exciting step forward which could potentially lead to better treatments or prevention in the future for millions around the world.”

However, the need for more research, plus rigorous testing, means any drug to prevent the condition is at least 15 years away.

As it would be aimed at children, it would have to be proved not to slow their overall growth, while still stopping their eyeballs from overdeveloping.

And genes are not the only factor behind the development of short-sightedness. A child’s lifestyle also plays a role, with too much time spent in front of a screen and lack of sunlight helping fuel the condition.

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