Haplogroup K is rare

“Ötzi” has no living descendants

The ice cream man "Ötzi" probably no longer has any living descendants. The analysis of the mitochondrial DNA of the early man trapped in the ice in the Tyrolean Alps 5,300 years ago showed that he belongs to a genetic line that is extremely rare and perhaps even completely extinct today.

In 1991 the mummified remains of a man who lived 5,300 years ago were discovered in the Tyrolean Alps. Since then, his death and his life have preoccupied research in many ways. Now a British-Italian research team led by Franco Rollo from the University of Camerino and Luca Ermini from the University of Leeds has investigated the mitochondrial DNA of the ice mummy "Ötzi" with the help of new technologies. The researchers compared their results with modern so-called haplogroups. Members of the same haplogroup share the same mtDNA sequences and go back to a common ancestor.

Mitochondrial DNA indicates relationships

"Changes in mitochondrial DNA are gradual as it is passed down through the generations," explains Martin Richards, professor of biology at the University of Leeds in the UK. "Therefore, it provides us with an effective way of tracing ancestors across the maternal line over thousands of years and determining relationships across entire human populations."

Since the DNA begins to decompose immediately after the death of an organism, the mtDNA of “Ötzi” is not complete either, but in numerous fragments. The researchers tested around 250 of these fragments several times to ensure that the results were not corrupted by reading errors. In the end, the scientists generated the oldest completely available section of a human mtDNA.

mtDNA subgroup of the ice mummy extinct or extremely rare

The result of the DNA comparisons showed that "Ötzi" belongs to haplogroup K1, which is still very common in Europe today. But all today's members of this group can be assigned to three subgroups, while the ice mummy belongs to a subgroup that has not yet been proven in people living today. The current results thus contradict an analysis of a smaller mtDNA piece from 1994, which indicated that the ice cream man might still have offspring in today's Europe.

"Our analysis confirms that Ötzi belongs to a previously unidentified line of K1 that has not been seen in modern European populations," explains Richards. “The frequency of genetic lines tends to fluctuate over time, partly due to the different numbers of offspring. As a result of this process of genetic drift, some gene variants die out. Our research suggests that Ötzi's line could also have died out. "

The researchers want to test whether this is actually the case by taking DNA samples from the population, particularly in the Alpine valleys, where Ötzi probably lived thousands of years ago. Because it cannot be ruled out that the line of this special subgroup of the mtDNA has survived here after all.

(University of Leeds, October 31, 2008 - NPO)

October 31, 2008