Tibetans Evolved to Survive High Life, Study Says

Most Tibetans are genetically adapted to life on the "roof of the world," according to a new study.

The Tibetan Plateau (map) rises more than 13,000 feet (4,000 meters) above sea level. At such heights, most people are susceptible to hypoxia, in which too little oxygen reaches body tissues, potentially leading to fatal lung or brain inflammation.

To survive the high life, many Tibetans carry unique versions of two genes associated with low blood hemoglobin levels, the researchers found.

Since hemoglobin is the oxygen-carrying component of red blood cells, the find might seem "really counterintuitive," said study leader Tatum Simonson at the University of Utah's Eccles Institute of Human Genetics in Salt Lake City.

"Usually, if you or I or any nonadapted person went to high altitude, we would increase our hemoglobin levels to compensate for the low amount of oxygen."

But high hemoglobin levels have been linked to complications such as hypertension and chronic mountain sickness, Simonson said.

These negative effects could have led to a genetic mutation among Tibetans that "prevented them from making as much" hemoglobin, she noted.

just take a good look at the topic "porphyria" and take a look at what many of them have as "symptoms".

Well, I did as you suggested. Here's how Wikipedia starts:

The acute, or hepatic, porphyrias primarily affect the nervous system, resulting in abdominal pain, vomiting, acute neuropathy, muscle weakness, seizures, and mental disturbances, including hallucinations, depression, anxiety, and paranoia. Cardiac arrhythmias and tachycardia (fast heart rate) may develop as the autonomic nervous system is affected. Pain can be severe and can, in some cases, be both acute and chronic in nature. Constipation is frequently present, as the nervous system of the gut is affected, but diarrhea can also occur.

You probably could just as well have pointed me to any genetic disorder. I see nothing here about whether people with this disorder, or really more importantly their descendants if they have any, are limited to breeding with others who have the same disorder. I think you probably know what I am after. Why don't you provide a couple of specific links to articles that provide support for the point you wish to make.

ML/NJ

Acute intermittent porphyria (AIP) would be a better search element.

One of the first things I noticed on doing a search on this topic today is that there's a NEW ONE ~ it says that a recent survey found HUNDREDS of different genes behind this problem in Scandinavia.

That's up from the 82 a few years back, or the 3 known 10 years ago.

No, this genetic difference is "special". The list of symptoms you found in Wiki doesn't begin to cover the situation ~ not at all ~

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