Category Archives: History

South Americans – only one wave of settlers?

Genetics, History, Human evolution

Nature reports: The meeting of the Society of American Archeology listened to Dr. Fehren-Schmitz, who presented the sequencing of human bone found in Peru at a site called Lauricocha. The remnants are from five individuals, two of them died around 9000 years ago, a third 2.500 years later and another a further 2300 years later, the fifth was dated. The sequences were derived from mitochondria and from the Y chromosome.

The results are in agreement with a single wave of migration. There might be earler migration but not necessarily. It is now up to investigator to sequence the actual indigenous population to see whether there are dicrepancies to this determination

Mixed origin for Europeans

Genetics, History

 The historic origin of Europeans is obviously much more complex than initially thought. Sciene reports from a meeting of biomolecular archaeology: Johannes Krause (Tübingen University, Germany) presented data that the European history started as late as there was migration from Africa: some 60000 years ago. These people were not the first settlers in Europe. They met the Neanderthals. And they were gatherers and hunters. These hunters eventually were invaded 9000 years ago by farmers from the Middle East. Note the farmers invaded the hunters/gatherers and not vice versa. To the great surprise of scientist involved there is a third source of DNA of Eurasian origin which was found in Scandinavia and Letonia, but not in the South of Europe. This “ghost” DNA was then found in boy from Sibiria who died some 24000 years ago.  You will not find a person with the same genome today, but part of it is present in North America and in Europe. The picture is a crude scheme of this development. We were told that an article will appear soon and we will tell you about.European Origin

90 Years of Renal Dialysis

History, In General, Medicinal technique,

Correct are the dates for 90 years of renal dialysis. A German doctor used a precursor of todays technique in 1924 for filtration of blood to get rid of deleterious low molecular weight (mass)  substances. The semipermeable membrane he used – and which is in principle still used today while the material itself has changed – is permeable only to low molecular weight substances which will cross the membrane and which will be diluted in the process. High molecular weight substances do not cross the membrane. If you pass blood along through such a filter which has on the outside a liquid (e.g. isotonic salt solution) , then the unwanted products cross the membrane due to the concentration difference. You pump this liquid permanently away , then the salts will stay in blood since there is no concentration difference between the blood and the outer liquid, the unwanted products like urea e.g., however, will diluted into the outer liquid and reduced in the blood.

The method applies to toxins and is used during renal failure for whatever reason.

Georg Haas was the first who applied this method to a patient in 1924. While he treated up to 11 patients the method was dismissed by collegues because it did not heal the patient, “only” approved the symptoms. Haas was very much engaged as the clinic head that he could not spent any further time for dialysis.

The breakthrough came with Willem Kolff (NL) 20 years later who used the easily available cellophane tubes which were originally produced to make sausages.

Tuberculosis in Peru – predating the contact with Europeans

Bacteria, History, Infection, Tuberculosis,

Devasting diseases have occured in indigenous populations of north and south America once they came in contact with Europeans. One disease, however, can no longer be attributed to this collection: tuberculosis.

In a Nature paper (doi:10.1038/nature13591) this week Bos, Harkins and colleagues demonstrate Mycobacterium tuberculosis isolates in Peruvian human skeletons from 1000 years ago i.e. 400 years before Columbus traveled to the Westindian islands. These mycobacteria do not ressemble the actual strains in Europe and America but are more closely related to those found in seals and sea lions proposing that human diseases could have spread via sea mammals before man themselves actually came in close contact. 

When Africans met Neanderthals some 50000 years ago: war and rape

Evolution, Genetics, History, Human evolution

There is an very interesting paper in Nature (doi:10.1038/nature12961) about the Neanderthal genom part in modern men. It shows an a chromosome by chromosome demonstration how much of the Neanderthal ancestry is found in the autosomes and in the sex chromosome: about 1 % in autosome and considerable less in sex chromomes. In the Y-chromosome it is barely found.

When the two populations first encounterd some 50000 years ago (as a paper form PLOS suggested: DOI: 10.1371/journal.pgen.1002947) we can envisage how this was done:  there was war and the Neanderthal female were raped after the man were killed. Whether this was a singular event or repeatingly done in the clash of general war betweem the two species is not documented, but when the progeny e.g. was selected for the “African” phenotyp then the Neatherthal would be not maintained in the Y chromosome.

Very suggestive! And much has not changed till modern times