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cyberdad
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19 Sep 2021, 1:08 am

In my previous career as a microbiologist I crossed paths with a famous West Australian microbiologist by the name Barry Marshall. Barry was responsible for the discovery of a gut bacteria called Helicobacter Pylori. Helicobacter was subsequently found to be responsible for the incidence of stomach cancer and Barry's discovery he received a Nobel prize in Medicine in 2005.

An interesting side-note is this bacteria is found in the stomachs of almost all human beings. Microbiologist discovered by chance that the genetic diversity of this bacteria supported a completely different field of research namely human evolution.

By the early 2000s genetic evidence was building up to support a theory called "Out of Africa" theory which supported a biological population phenomenon that was present in the human genome called the "Serial founder effect". Based on genetic diversity in humans, this theory strongly supports the idea that the human species evolved in east Africa and then branched off into different populations with with one segement represented by the L3 haplogroup moving out of Africa around 70,000 years ago. While there are multiple haplogroups in Africa only the L3 haplogrpoup is represented by every population outside of Africa.

Secondly the populations outside of Africa show DNA from neanderthals and Denisovans which lived in Eurasia but are absent in Africa.

Despite the overwhelming evidence for the out of Africa hypothesis, many scientists have held onto an outdated theory called the multireigional hypothesis where primitive pre-humans evolved in different geographic regions all over the world and evolved into Homo Sapiens separately. In some countries in the former Soviet Union, South America and particularly in China the science curriculum does not permit the teaching of "Out of Africa" theory. In China resources have been allocated to disproving this theory
https://www.newscientist.com/article/dn ... ca-theory/

The recent research on Helicobacter indicating a long association between the gut bacteria and all early humans will finally render these fantasies in China (and elsewhere) that some mystical power bestowed a heavenly mandate on the Chinese as a chosen people who evolved separately in China,

The incidence of Helicobacter in China is highly prevalent so assuming the CHinese ministry of education is correct then the genetic diversity of helicobacter in China should be greater than outside of China demonstrating the evolution of humans in China. But an article published in the prestigious journal Nature demonstrated anatomically modern humans were already infected by H. pylori before their migrations from Africa and demonstrate that H. pylori has remained intimately associated with their human host populations ever since.
https://www.nature.com/articles/nature05562

I like this story as it illustrates how science can destroy widely held beliefs that are tenaciously held onto for cultural reasons.



naturalplastic
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19 Sep 2021, 5:14 pm

Interesting. For a number of reasons. Interesting how gut bacteria, like body lice DNA, can yield clues about human evolution.

Also interesting how now that China is flexing its muscles - it just as imperialistic and ethnocentric in prejudices about human evolution as the Victorian Brits who all fell for the "Piltdown Man" hoax were in 1920. The Piltdown man was a skull found in Piltdown common in England that turned out to be mash up of human and ape skull fragments that were filed down to fit each other...and baked to looked aged. But...we all KNOW that the first man on the planet MUST have been an Englishman. Certainly not an African. So Piltdown man fit right into their notions.And was an accepted part of textbooks for like 30 years.