New Research offers unexpected clues about modern evolutionary changes

A case of natural selection on the Tibetan Plateau

A new study recently revealed the interesting intricacies of modern-day natural selection and how the environments in which we live today, like the Tibetan Plateau, are still pushing humans to grow and change.

Humans can’t just live anywhere on Earth

There are some places in the world where humans aren’t very well suited to live. One of those is in the high-altitude conditions of the world’s tallest peaks. People fall victim to a strange problem known as altitude sickness. 

Some can thrive in inhospitable places

However, some humans have developed the ability to thrive in even the harshest of high-altitude locations. Where are they? You may have guessed it already. That’s right, the Tibetan Plateau. 

People living in the Tibetan Plateau

Humans have been living in the Tibetan Plateau for roughly ten thousand years, and in all that time, the people who have come to call the area home have developed the ability to thrive in the oxygen-starved region. 

Photo Credit: Wiki Commons, Public Domain

Tibetans have some interesting traits

According to Science Alert, the people living in the Tibetan Plateau have changed in a way that allows their red blood cells to carry more oxygen to their body’s tissues, which allows them to thrive in an otherwise perilous environment. 

Altitude sickness and hypoxia

Altitude sickness is essentially just the result of a lack of oxygen making it to the body’s tissue. Also known as hypoxia, the condition has taken down many mountaineers, but it doesn’t affect some people living in the Tibetan Plateau in the same way.

A study revealed something interesting

Why the inhabitants aren’t affected by hypoxia was partly the subject of a recent study published in the journal Proceedings of the National Academy of Sciences that found people living in the Tibetan Plateau have evolved to adapt to the region’s challenges. 

A fascinating field of study

"Adaptation to high-altitude hypoxia is fascinating because the stress is severe, experienced equally by everyone at a given altitude, and quantifiable," anthropologist Cynthia Beall of Case Western Reserve University explained to ScienceAlert.

An example of biological variation

"It is a beautiful example of how and why our species has so much biological variation,” Beall added. She has been studying human responses to hypoxia for years and discovered something interesting about Tibetan communities. 

Insight into a special Tibetan trait

According to the research, Tibetans have developed a specific set of traits that allow their blood to deliver more oxygen to the tissue in their bodies and these traits appear to be passed down from mothers to their babies, which sounds a lot like the evolutionary process. 

Studying women in Tibetan communities

Beall and her team decided to study a group of 417 women aged from 46 to 86 who had also lived in Nepal at altitudes above 3,500 meters or 11,480 feet. But why only look at women and such a specific age group? There was an important reason. 

Maximizing success in harsh environments

According to Science Alert, women are most likely to carry the traits that maximize the success of an individual in a given environment. They are also likely to be found in those who survive the stress of childbirth and pregnancy. 

Why look at women?

“These women are more likely to give birth to more babies; and those babies, having inherited survivability traits from their mothers, are also more likely to survive to adulthood, and pass the traits on to the next generation,” Science Alert explained. 

What did the researchers examine?

Beall and her team looked at the levels of protein (hemoglobin) in the red blood cells of the women they studied and analyzed their ability to carry oxygen to their tissues. In a surprise finding, the researchers discovered something very weird. 

What did researchers discover?

The women who had the most live births had hemoglobin levels that were about average for the test group but their oxygen saturation level was very high. This suggested their bodies adapted to deliver more oxygen to their tissues without thickening their blood.  

How some Tibetan women were different

Science Alert explained that the adaptations in some of the women would ultimately place more stress on their hearts as they struggled to pump more oxygen-rich, and therefore thicker, blood that was resistant to flow throughout their bodies. 

Making the most of the oxygen available

The women who had had the most live births also had a high rate of blood flow to their lungs and wider left ventricles in their hearts, which when looked at together suggested their adaptations allowed them to “make the most of the low oxygen in the air" Science Alert explained. 

Photo by Robina Weermeijer on Unsplash