problem frequently encountered in the analysis of DNA genetics of ancient people and animals – contamination – solved: Scientists have found a method of purification of DNA from more recent pollution and estimate the sample belonging to Neanderthal cave Okladnikova defining its place in the genetic tree.
Contamination – chemical and biological term infection Connection foreign substances alien biological material. Ancient DNA of humans and animals may be contaminated as the microenvironment, where the remains of the body, and DNA scientists working with found samples. Such pollution is undoubtedly an obstacle in DNA sequencing (determining the amino acid or nucleotide sequence) – a process that is used to describe the structure of DNA.
Contacthominids sucked from the finger
comparison of genomes of Neanderthals and modern humans denisovtsev showed that different groups of hominids 12-126 thousand years ago, met and talked … ?
group of researchers from Sweden and Germany led by Pontus Skoglund (Uppsala University), as well as collaboration of Russian scientists Michael Shunkova and Anatoly Derevyanko (Institute of Archaeology and Ethnography of the Russian Academy of Sciences) found a method of cleansing the ancient DNA from external contaminants, and has analyzed the DNA of the remains of a Neanderthal cave Okladnikova. In the work of scientists participated Svante Pääbo and , a geneticist who has received the full version of the Neanderthal genome.
Full results of genetics can be found in the journal PNAS .
Method for determination of extraneous DNA layers based on an analysis of its natural mutations. For example, 30-40% of the samples, dating back several thousand years, cytosine is converted into thymine, adenine and guanine in. Scientists have developed a system that simulates the processes of natural DNA changes and compares the results with the data sample.
Denisovets had relatives in Spain
Denisovskoye The ancient man whose remains were found in Siberia, and the hominids who lived in Spain 400 thousand years ago, had a common ancestor. Such … ?
To test the new method, the researchers used approximately 1 million DNA sequences derived from the remains of Australian numbering 100 years, four skeletons from the Neolithic period (found in Scandinavia about 5 thousand years ago), from four skeletons of Neanderthals (age: 38 to 70 million years old) and four modern living people. System showed the presence of foreign pieces of DNA samples with age. Next, the researchers deliberately contaminated the DNA of modern man “parts” of Neanderthal DNA – and again the system has proven its effectiveness by evaluating the “extra” items.
Thus, at the moment of genetics have at their disposal a method of purification of ancient DNA from foreign elements that will have a significant positive effect on DNA research.
Indians came from Siberia
team of scientists, which included seven scientists from Russia, including the Russian Academy of Sciences, Academy of Medical Sciences and the Hermitage, the gene studied the ancient inhabitants of the Upper Siberia … ?
This is confirmed and further the work of scientists. Group Pontus Skoglund studied Neanderthal DNA, whose remains were found in a cave Okladnikova (located on the outskirts of the village Sibiryachiha Soloneshensky Altai Region). Genetics took mitochondrial DNA sequences of 6906 and were analyzed using the system for the detection of contaminants. Firstly, analyzing natural mutations, the system confirmed that the sample really belongs Neanderthal and then revealed 10.2% contaminated fragments. To get rid of them, the scientists had to reduce the number of investigated sequences to 3908, pollution levels decreased to 1,3%.
DNA sequencing showed that the sequence of the mitochondrial genomes of Neanderthal cave Okladnikova does not coincide with the previously described sequences of Neanderthals from Central and Western Europe, but takes its place in the genetic cluster with them.
Work Group Pontus Skoglund unequivocally proved that the establishment of a system for separating contaminants from the DNA will allow geneticists to conduct a more detailed analysis of samples of genes ancient people and animals, and thus a step closer to deciphering them embedded in the DNA helix secrets.
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