•   
  •   
  •   

Technology 'Sea Nomads' Are First Known Humans Genetically Adapted to Diving

09:50  20 april  2018
09:50  20 april  2018 Source:   nationalgeographic.com

Genetic Hack Makes Plants Use 25 Percent Less Water

  Genetic Hack Makes Plants Use 25 Percent Less Water The planet will face a 40 percent water deficit if global warming continues at its current pace, according to the United Nations, highlighting the importance of efficient agricultural practices. Researchers unveiled March 6 a genetic modification that enables plants to use a quarter less water with scant reduction in yield.By altering a single gene, scientists coaxed tobacco plants — a model crop often used in experiments — to grow to near normal size with only 75 percent of the water they usually require.

If you hold your breath and plunge your face into a tub of water, your body automatically triggers what's called the diving response. Your heart rate slows, your blood vessels constrict, and your spleen contracts, all reactions that help you save energy when you're low on oxygen.

As a human dives deeper into the water, the increase in pressure causes the lung's blood vessels to fill with more blood. In extreme cases, the vessels can However, the sea nomad lifestyle is increasingly under threat. They're considered marginalised groups that don't enjoy the same citizenship rights as

a person swimming in a body of water: A young Bajau man named Dido fishes for coral fish and shells off Mantabuan Island. © Photographb by Matthieu Paley, National Geographic A young Bajau man named Dido fishes for coral fish and shells off Mantabuan Island.

If you hold your breath and plunge your face into a tub of water, your body automatically triggers what's called the diving response. Your heart rate slows, your blood vessels constrict, and your spleen contracts, all reactions that help you save energy when you're low on oxygen.

Most people can hold their breath underwater for a few seconds, some for a few minutes. But a group of people called the Bajau takes free diving to the extreme, staying underwater for as long as 13 minutes at depths of around 200 feet. These nomadic people live in waters winding through the Philippines, Malaysia, and Indonesia, where they dive to hunt for fish or search for natural elements that can be used in crafts.

This Camera Can See the Mantis Shrimp's Invisible World

  This Camera Can See the Mantis Shrimp's Invisible World To the human eye, adapted for land, the underwater landscape can appear too dim, too blurry, and too blue. It’s easy to get lost. To mantis shrimp, however, the ocean environment is richly textured and varied. For a small glimpse of the mantis shrimp’s view of the ocean, humans can now look through a mantis-shrimp-inspired camera from a team led by Viktor Gruev, an engineer at the University of Illinois Urbana-Champaign.

' Sea Nomads ' Are First Known Humans Genetically Adapted to Diving For hundreds of years, the Bajau have lived at sea , and natural selection may have made

Evidence that humans can genetically adapt to diving has been identified for the first time in a new study. The evidence suggests that the Bajau, a people For over 1000 years the Bajau people, known as ' Sea Nomads ', have travelled the Southeast Asian seas in houseboats and collected food by free

Now, a study in the journal Cell offers the first clues that a DNA mutation for larger spleens gives the Bajau a genetic advantage for life in the deep.

Leaning on the Spleen

Of all the organs in your body, the spleen is perhaps not the most glamorous. You can technically live without it, but while you have it, the organ helps support your immune system and recycle red blood cells.

Previous work showed that in seals, marine mammals that spend much of their life underwater, spleens are disproportionately large. Study author Melissa Llardo from the Center for Geogenetics at the University of Copenhagen wanted to see if the same characteristic was true for diving humans. During a trip to Thailand, she heard about the sea nomads and was impressed by their legendary abilities.

Humans Have Caused Mammals to Shrink

  Humans Have Caused Mammals to Shrink A new study found the average size of mammals has decreased over the last 100,000 years because of human activity.The size of the average mammal has been shrinking for more than 100,000 years – and it's all because of humans.

The first known humans to be genetically adapted to diving , the Bajau " sea nomads " in the Philippines, Malaysia, and Indonesia, shed light on Published in Cell and entitled “ Physiological and Genetic Adaptations to Diving in Sea Nomads ” it lays out the evidence that the indigenous Bajau.

For hundreds of years, the Bajau have lived at sea , and natural selection may have made them genetically stronger divers . Most people can hold their breath underwater for a few seconds, some for a few minutes. But a group of people called the Bajau takes free diving to the extreme, staying

“I wanted to first meet the community, and not just show up with scientific equipment and leave,” she says of her initial travels to Indonesia. “On the second visit, I brought a portable ultrasound machine and spit collection kits. We went around to different homes, and we would take images of their spleens.

“I usually had an audience,” she adds. “They were surprised I had heard of them.”

She also took data from a related group of people called Saluan, who live on the Indonesian mainland. Comparing the two samples back in Copenhagen, her team found that the median size of a Bajau person's spleen was 50 percent bigger than the same organ in a Saluan individual.

“If there's something going on at the genetic level, you should have a certain sized spleen. There we saw this hugely significant difference,” she says.

The researchers also stumbled across a gene called PDE10A, which is thought to control a certain thyroid hormone, in the Bajau but not the Saluan. In mice, the hormone has been linked to spleen size, and mice that are manipulated to have lower amounts of the hormone have smaller spleens.

Early humans probably enjoyed a giant sloth snack

  Early humans probably enjoyed a giant sloth snack Unlike modern sloths, which spend their time vegging out in trees in South and Central America, ancient giant sloths were the size of an ox…In a paper published today (April 25) in Science Advances, a team led by scientists from the University of Arizona and the US National Parks Service report scouring the grounds of the White Sands National Monument in New Mexico for evidence of the historical relationship between humans and giant sloths. The White Sands monument, a park-like area full of sand dunes, contains footprints left by all kinds of ancient creatures.

Physiological and Genetic Adaptations to Diving in Sea Nomads . Gibbens, Sarah. ‘ Sea Nomads ’ Are First Known Humans Genetically Adapted to Diving .

' Sea Nomads ' Are First Known Humans Genetically Adapted to Diving . Students in Biology 442 dissect human bodies that have been donated for science.

Llardo theorizes that over time, natural selection would have helped the Bajau, who have lived in the region for a thousand years, develop the genetic advantage.

Under Pressure

While the spleen might partially explain how the Bajau dive so well, other adaptations may be at play, too, says Richard Moon from the Duke University School of Medicine. Moon studies how the human body responds to both high altitudes and extreme depths.

As a human dives deeper into the water, the increase in pressure causes the lung's blood vessels to fill with more blood. In extreme cases, the vessels can rupture, causing death. In addition to genetically inherited adaptations, regular training could help prevent that effect.

“The lung chest wall could become more compliant. There could be some looseness that develops over your training. The diaphram could become stretched. The abs could become more compliant. We don't really know if those things occur,” he says. “The spleen is able to contract to some extent, but we don't know of any direct connection between thyroid and spleen. It may well be.”

Gut check: Swallowed capsule could spot trouble, send alert

  Gut check: Swallowed capsule could spot trouble, send alert Scientists have developed a swallowed capsule that might someday be used to spot health problems from inside the gut. It's packed with tiny electronics and millions of genetically engineered living cells. Researchers at the Massachusetts Institute of Technology tested the capsule in pigs and reported the results Thursday in the journal Science.The capsule was tested in pigs and correctly detected signs of bleeding, researchers at the Massachusetts Institute of Technology reported Thursday in the journal Science . At more than an inch long, it will have to be made smaller for testing in people.

Cynthia Beall is an anthropologist from Case Western Reserve University who has studied people living in extremely high altitudes, including Tibetans said to live at the “roof of the world.” She thinks Llardo's study opens up interesting research opportunities but needs to see more measurable biological evidence before she's convinced that a genetic trait is helping the Bajau become better divers.

“You could measure the spleen more, for example, strength of contractions of the spleen,” she says.

What Can We See From the Sea?

In addition to understanding how the Bajau became such good free divers, Llardo says the findings have medical implications.

The dive response is similar to a medical condition called acute hypoxia, in which humans experience a rapid loss of oxygen. The condition is often a cause of death in emergency rooms. Studying the Bajau could effectively act as a new laboratory for understanding hypoxia.

However, the sea nomad lifestyle is increasingly under threat. They're considered marginalized groups that don't enjoy the same citizenship rights as their mainland counterparts. Increased industrial fishing is also making it harder for them to subsist on local stocks. As a result, many choose to leave the sea.

Without support for their way of life, Llardo worries that the Bajau and the lessons they can impart about human health may not be around for much longer.

Cuddles may influence babies' DNA .
Researchers have made an unexpected discovery about the powers of a parent's cuddle for their child: they may be able to modify the DNA in their brain cells. The more the parent nurses, the less the baby undergoes a phenomenon at the origin of a multiplication of certain DNA sequences: backtransposition. As a result, less stress in adulthood and better adaptation to their environment in the pampered little ones, compared to those deprived of maternal affection.

Topical videos:

usr: 1
This is interesting!