Sunday, January 17, 2010

The Jewish Priesthood Cohanim and the Y Chromosome Cohen Modal Haplotype (CMH)

Extended Y chromosome haplotypes resolve multiple and unique lineages of the Jewish priesthood, by
Hammer MF, Behar DM, Karafet TM, Mendez FL, Hallmark B, Erez T, Zhivotovsky LA, Rosset S, Skorecki K
"[Abstract (excerpt)]

The most frequent Cohanim lineage (46.1%) is marked by the recently reported P58 T->C mutation, which is prevalent in the Near East. Based on genotypes at 12 Y-STRs, we identify an extended CMH on the J-P58* background that predominates in both Ashkenazi and non-Ashkenazi Cohanim and is remarkably absent in non-Jews. The estimated divergence time of this lineage based on 17 STRs is 3,190 +/- 1,090 years. Notably, the second most frequent Cohanim lineage (J-M410*, 14.4%) contains an extended modal haplotype that is also limited to Ashkenazi and non-Ashkenazi Cohanim and is estimated to be 4.2 +/- 1.3 ky old. These results support the hypothesis of a common origin of the CMH in the Near East well before the dispersion of the Jewish people into separate communities, and indicate that the majority of contemporary Jewish priests descend from a limited number of paternal lineages."

DNA, mtDNA, Haplogroups and Chronlology

Researchers Develop Method for Distinguishing Ancient Human DNA from Modern Day Contaminants | GenomeWeb Daily News | Sequencing | GenomeWeb
"NEW YORK (GenomeWeb News) – Researchers from the Max Planck Institute for Evolutionary Anthropology and the Russian Academy of Sciences have come up with a way to overcome modern human DNA contamination — a major obstacle in past ancient human DNA sequencing efforts....

Based on the DNA patterns present in mitochondria, the researchers concluded that the Russian remains are roughly 30,000 years old — in the same range as previous estimates that put the skeleton's age at between 30,000 and 33,000 years old....

The team is currently trying to collect more samples from early modern human populations. And the new method may have applications for studies of historical population patterns throughout Europe and elsewhere, Krause explained, such as the effects of an ice age occurring in Europe around 20,000 years ago."

DNA analysed from an early European

Paul Rincon, Science Reporter at BBC News, reports that DNA was recently analysed from an early European at the ancient site of Kostenki. As published in Current Biology, the DNA analyzed was mitochondrial DNA (mtDNA) - passed down from a mother to her offspring - and discovered to be mtDNA of the haplogroup U2.

Johannes Krause, Adrian W. Briggs, Martin Kircher, Tomislav Maricic, Nicolas Zwyns, Anatoli Derevianko, and Svante Pääbo, A Complete mtDNA Genome of an Early Modern Human from Kostenki, Russia.
"Summary

The recovery of DNA sequences from early modern humans (EMHs) could shed light on their interactions with archaic groups such as Neandertals and their relationships to current human populations. However, such experiments are highly problematic because present-day human DNA frequently contaminates bones [1] and [2]. For example, in a recent study of mitochondrial (mt) DNA from Neolithic European skeletons, sequence variants were only taken as authentic if they were absent or rare in the present population, whereas others had to be discounted as possible contamination [3] and [4]. This limits analysis to EMH individuals carrying rare sequences and thus yields a biased view of the ancient gene pool. Other approaches of identifying contaminating DNA, such as genotyping all individuals who have come into contact with a sample, restrict analyses to specimens where this is possible [5] and [6] and do not exclude all possible sources of contamination. By studying mtDNA in Neandertal remains, where contamination and endogenous DNA can be distinguished by sequence, we show that fragmentation patterns and nucleotide misincorporations can be used to gauge authenticity of ancient DNA sequences. We use these features to determine a complete mtDNA sequence from a not, vert, similar30,000-year-old EMH from the Kostenki 14 site in Russia."


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