October 30, 2008

Complete mtDNA sequence of Tyrolean Iceman

It remains to be seen whether or not the mtDNA branch of the Iceman's sequence will turn up in modern Europeans. Quite a lot of people are ordering full-mtDNA sequences these days, and this is probably going to continue and intensify (unless the global economy completely implodes).

Still, the finding that the Iceman had such a unique genetic sequence is consistent with the idea that selection has had an effect on human mtDNA diversity, effectively causing the mtDNA gene pool to be dominated by a few successful lineages, with many older lineages not persisting to the present. This is not unique to humans but may be shared with our oldest animal friend.

UPDATE (31 Oct): Blaine Bettinger informs me that there may be a second independent attempt at sequencing the Iceman's mtDNA that did find a modern relative:
According to the article, Alan Cooper - head of the University of Adelaide’s Australian Center for Ancient DNA - has also sequenced Otzi’s mtDNA and stated that "We have found someone very, very closely related." I’m looking forward to comparing the mtDNA genome obtained by the two research groups. Will they be the same?
John Hawks suggests selection for the disappearance of the "Iceman clade" from the modern mtDNA gene pool, but also quotes Antonio Torroni to the effect that his idiosyncratic mtDNA may be due to a reversal:
It’s possible but unlikely that Ötzi belonged to a fourth branch of K1 that is now extinct or rare, Torroni says. He considers it more probable that a random mutation in the Iceman’s mitochondrial DNA erased the only genetic marker currently used to identify members of the most common K1 branch.

Current Biology doi: 10.1016/j.cub.2008.09.028

Complete Mitochondrial Genome Sequence of the Tyrolean Iceman

Luca Ermini et al.


The Tyrolean Iceman was a witness to the Neolithic–Copper Age transition in Central Europe 5350–5100 years ago, and his mummified corpse was recovered from an Alpine glacier on the Austro-Italian border in 1991 [1]. Using a mixed sequencing procedure based on PCR amplification and 454 sequencing of pooled amplification products, we have retrieved the first complete mitochondrial-genome sequence of a prehistoric European. We have then compared it with 115 related extant lineages from mitochondrial haplogroup K. We found that the Iceman belonged to a branch of mitochondrial haplogroup K1 that has not yet been identified in modern European populations. This is the oldest complete Homo sapiens mtDNA genome generated to date. The results point to the potential significance of complete-ancient-mtDNA studies in addressing questions concerning the genetic history of human populations that the phylogeography of modern lineages is unable to tackle.



Crimson Guard said...

Here's a reconstruction of the 5'4" encino man..well I suppose its him,


cacio said...

When I go to Italy, I must really make an effort to go to that museum...

Regarding the mtdna, as Bill Hurst was pointing out in another blog, K1 is one of the most frequent lineages in Europe. Nobody has all the specific mutations of Otzi, but there are other isolated K1. It's not that it is a deep lineage that disappeared. Most lineages so far have no matches. For instance, my own mtdna has not even HVR1 matches. Otzi's HVR1 would match millions of people.



ergosum said...

I just looked up
http://www.landschaftsmuseum.de/Bilder/Oetzi-Rek_Ausschn-1.jpg and found that he guy looks like Pavarotti. Makes sense!

miz RAND BLOWTON said...

Pavarotti looks like Otzi on steroids, he's workin' totally different DNA if you ask me. Cacio above is right-that Otzi's Mt K1 is not too rare,lots of modern folks got it,but Otzi's particular strain of it died out long ago with him-same will probably will happen to most people unless they get to breedin' a whole lot of their own strain of something.