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    Genetic research sheds light on pre-Inca Tiwanaku civilization

    One of the most powerful pre-Inca civilizations in South America – Tiwanaku – was much more genetically homogeneous than previously thought, according to genetic research conducted by a team of Polish scientists.

    The Tiwanaku civilization existed from the 6th – until probably the early 12th century. It covered areas of today’s Peru, Bolivia, and Chile. It is named after the resort located next to Lake Titicaca. In Tiwanaku to this day are preserved remains of monumental stone temples and buildings, testifying to the ancient power of this civilization. Its origins and end are still mysterious to archaeologists.


    “Our latest genetic research shows that, contrary to earlier views, the representatives of the Tiwanaku civilization were definitely more genetically homogeneous than previously thought,” Prof. Ziółkowski told PAP.


    Such a conclusion is the result of cooperation between his team and palaeogeneticists from the University’s Centre for New Technologies (CENT) and a group of foreign researchers. An article on this topic has just appeared in Science Advances (DOI:10.1126/sciadv.abg7261).


    Based on genetic studies, the researchers concluded that the core part of the rural population living around Lake Titicaca had not been influenced by any major migrations from outside for several hundred years.


    According to researchers, it was different in the metropolis itself (Tiwanaku), which was a religious center, a place of pilgrimage, where people from many areas of the southern Andes met for religious ceremonies and then returned to their home settlements. However, not everyone.


    “We found the presence of newcomers from southern Peru and even one individual coming from the distant Amazon. It was sacrificed,” pointed out CENT geneticist Dr. Danijela Popović.


    As she added, the examination of the remains of two people shows that they also had nearby ancestors from the Amazon area in addition to those from the Lake Titicaca area.


    “This is interesting information because until now it was not known whether the artifacts found at the site associated with the Amazon region, such as the necklace made of jaguar teeth, indicate only trade – or the presence of people from the Amazon area,” Professor Ziółkowski stressed.


    Fossil DNA – that is, the DNA preserved in human remains after an organism dies – is exposed to the environment in which the remains are found, causing it to degrade and fragment. This has been quite a handicap in recent research. Out of almost a hundred samples taken, satisfactory information could be obtained from about 20.


    “Despite the difficulties, using state-of-the-art techniques, we have doubled the amount of known genomic data available for pre-Columbian populations from within Bolivia,” Dr. Popovićc noted.


    In addition to her, the palaeogenetic analysis was carried out by Dr. Martyna Molak and Dr. Mateusz Baca, at the Laboratory of Palaeogenetics and Conservation Genetics at the University of Warsaw’s Centre for New Technologies. This was possible thanks to funding from NCN.


    The samples taken from human remains for genetic research are also very precisely dated using the AMS 14C method by laboratories in Poznan and Waikato (New Zealand). Therefore, researchers can much more precisely reconstruct the phenomena studied and place them on a timeline because until now the age of the remains was determined based on the monuments accompanying them.


    “It turned out, for example, that the people who were sacrificed in the declining Tiwanaku period around the middle of the 10th century were from the Lake Titicaca area and had no foreign +admixtures+. This may indicate a narrowing of the scope of influence of this political body in that period,” Professor Ziółkowski pointed out.


    It is still unclear what caused the collapse of the Tiwanaku state. It was thought, for example, that decades-long droughts that destroyed the floodplain cropping system of the fields may have contributed. However, more recent research suggests that the fields were still being cultivated. There might have been social revolt, although the reason for it is not clear, as evidenced by the intentional destruction of some of the shrines,” stressed Prof. Ziolkowski.


    He pointed out that genetic research was possible thanks to the help of Bolivian as well as American and Polish researchers, who made available materials obtained during previous excavations both in Tiwanaku itself and in satellite sites.


    “Particularly noteworthy is the contribution of the American archaeologist Dr. Alexei Vranich, who is working with us – the discoverer of one of the main human sacrifices at Tiwanaku,” Prof Ziółkowski said.


    Polish research on Tiwanaku culture began in 2007 as part of a Polish-Italian-Bolivian excavation project at a previously unexplored temple called Kantatallita.


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