Interesting Genetic Finding

[vorlon13]

Many possible mutations would confer advantage for high altitude living.

More efficient hemoglobin

or more red blood cells

or more efficient use of oxygen by muscle cells

or better lungs

or more oxygen storage capacity in tissues

or less restrictions in sinus passages

or less susceptibility to edema at altitude

or better absorption of nutrients that help high altitude acclimatization

or the ability to acclimatize faster

or the ability to start to acclimatize at a lower altitude

or the ability to shunt oxygen away from digestion (or something) and towards musculature


Someone trained in physiology could probably come up with a hundred more. And of course, these favorable mutations should not have a disadvantage, increased susceptibility to viruses, for instance, or that make bones brittle. Probably thousands of ways to have something good go wrong, under the right conditions.

[Minimalist]

DNA testing on the 41,000-year-old bone indicated Denisovans were distinct from our species and Neanderthals.

But not distinct enough to be unable to interbreed.

In biology, a species (plural: species) is one of the basic units of biological classification and a taxonomic rank. A species is often defined as the largest group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, the difficulty of defining species is known as the species problem.

http://en.wikipedia.org/wiki/Species

We desperately need a specimen of Homo Erectus DNA to examine. This



could be everyone's Great to the nth degree Grand Pappy.

[Jackalope]

For once I was trying to avoid swearing.

What the fuck for?

[Anomalocaris]

One wonders if Neanderthals, Homo sapiens, denisovans and homo erectus might have at one time been nodes on a system of ring species, that is to say each of these populations have neighboring populations with whom they could interbreed. Genes could flow from one node through one or more neighboring, intermediate populations to reach any other other node. But some of the nodes might not directly interbreed.

[ignoramus]

Intelligence is evolutionary.
If all mankind died of a new virus tomorrow, how long to you think before something else starts typing on forums.
10k years? 50k?

[Minimalist]

Intelligence is evolutionary.

You think so?




I don't.

[ignoramus]

One Brain for sale ...asking top dollar.
Brand new! Never been used!

[The Grand Nudger]

Since this allegedly denisovans sourced gene said to be important to high altitude living is found nowhere else other than in majority of Tibetans and a small handful of Han Chinese, how do the natives south Americans of the Andes cope with living in altitude?

Why would the denisovans possess a widespread special adaptation to high altitude?

Birds and bees achieve flight in entirely dissimilar ways. Squirrels "achieve flight" by not flying at all - but what they do still works. Apply that to the Andes.

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Andeans[edit]
The Andes highlanders are known for centuries, such as from the 16th century missionaries, that their reproduction has always been absolutely normal, without any effect in the giving birth or the risk for early pregnancy loss, which are common to hypoxic stress.[33] They have developmentally acquired enlarged residual lung volume and its associated increase in alveolar area which are supplemented with increased tissue thickness and moderate increase in red blood cells. Though the physical growth in body size is delayed, growth in lung volumes is accelerated.[34] In contrast to the Tibetans, the Andeans, who have been living at high-altitudes for no more than 11,000 years, do not show unique haemoglobin level, instead they exhibit the same elevated haemoglobin concentrations that lowlanders exhibit at high elevations. However, they do have increased oxygen level in their haemoglobin, that is, more oxygen per blood volume than other people. This confers an ability to carry more oxygen in each red blood cell, a more effective delivery system of oxygen throughout their bodies than other people, while their breathing is essentially at the same rate.[30] This enables them to overcome hypoxia and normally reproduce without risk of death for the mother or baby. But elevated haemoglobin levels still leave them at risk for mountain sickness with old age.



Quechua woman with llamas
Among the Quechua people of the Altiplano, there is a significant variation in NOS3 (the gene encoding endothelial nitric oxide synthase, eNOS), which is associated with higher levels of nitric oxide in high altitude.[35] Nuñoa children of Quechua ancestry exhibit higher blood-oxygen content (91.3) and lower heart rate (84.8) than their counterpart school children of different ethnicity, who have an average of 89.9 blood-oxygen and 88-91 heart rate.[36] High-altitude born and bred females of Quechua origins have comparatively enlarged lung volume for increased respiration.[37]



Aymara ceremony
Blood profile comparisons show that among the Andeans, Aymaran highlanders are better adapted to highlands than the Quechuas.[38][39] Among the Bolivian Aymara people, the resting ventilation and hypoxic ventilatory response were quite low (roughly 1.5 times lower), in contrast to those of the Tibetans. The intrapopulation genetic variation was relatively less among the Aymara people.[40][41] Moreover, unlike the Tibetans, the blood haemoglobin level is quite normal among Aymarans, with an average of 19.2 g/dl for males and 17.8 g/dl for females.[42] Among the different native highlander populations, the underlying physiological responses to adaptation are quite different. For example, among four quantitative features, such as are resting ventilation, hypoxic ventilatory response, oxygen saturation, and haemoglobin concentration, the levels of variations are significantly different between the Tibetans and the Aymaras.[43] The Andeans, in general are the most poorly adapted, as particularly shown by their frequent mountain sickness and loss of adaptative characters when they move to lowlands.[44]
http://en.wikipedia.org/wiki/High-altitu..._in_humans

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-and there we are.