May 28, 2009

Ancient mtDNA from Pompeii

From the paper:
The aim of this study was to investigate family relationships among the inhabitants of Cajus Iulius Polybius’ house. In addition, the mtDNA haplogroup attribution of these individuals was considered.


Regarding the mtDNA haplogroups, individuals 3A, 3B, 2A, 2B, 2C, 3D most likely belong to haplogroup T2b (Malyarchuk & Derenko, 1999; Pike, 2006; Richards et al., 2000), which in modern Italians ranges between 4.4 and 4.7% (A. Torroni, personal communication). The polymorphisms in positions 16294 and 16304 detected in individuals 3A, 3B, 2A, 2B, 2C, 3D in haplogroup T2b are often associated with the polymorphism at nucleotide 16296 (Pike, 2006; Richards et al., 2000). The absence of this mutation in our individuals is probably due to the instability of this nucleotide in haplogroup T2b (Malyarchuk & Derenko, 1999; Richards et al., 2000; Pike, 2006).


Individual 1A, besides the polymorphism at position 16399 in HVS1, shows a sequence identical to rCRS at position 7028 hence we might assume that he most likely belongs to haplogroup H (Torroni et al., 1996). Individual 1B, showing polymorphisms at positions 16292 and 16298 and a sequence identical to rCRS at positions 73 and 4580, most likely belongs to haplogroup HV0 (Achilli et al., 2007; Pierron et al., 2008).


For individual 5,6A, who shows a polymorphism at positions 16391 and 73, and for 5,6B who shares the rCRS in HVS1 and at position 73, we can conclude that while individual 5,6A cannot be attributed to haplogroup H, individual 5,6B most likely can be (Torroni et al., 1996).
Some pictures from the house of Polybius.

Annals of Human Genetics

Ancient DNA and Family Relationships in a Pompeian House

Giovanni Di Bernardo et al.


Archaeological, anthropological and pathological data suggest that thirteen skeletons found in a house at the Pompeii archaeological site, dated to 79 A.D., belong to one family. To verify this and to identify the relationships between these individuals, we analyzed DNA extracted from bone specimens. Specifically, hypervariable segment 1 (HVS1) of the human mitochondrial DNA (mtDNA) control region was amplified in two overlapping polymerase chain reactions and the sequences were compared to the revised Cambridge Reference Sequence. As independent controls, other polymorphic sites in HVS1, HVS2 and in the coding region were analyzed. We also amplified some short tandem repeats of the thirteen specimens. This study revealed that six of the thirteen individuals are indeed closely related.



Maju said...

They were probably relatives, what would explain the aboundance of a relatively rare clade like T2b.

Anyhow, how did they manage to extract DNA from what are technical fossils? I understand that Pompeians bodies were fully fossilized (their bodies replaced by stone) and not just covered on ashes (that would eventually become rock). Am I wrong on that?

Gioiello said...

"Caius Iulius Polybius" seems a freedman's surname, then I think it is difficult to link his mitochondrial to a definite ethnic group. Probably he was a freedman of the Imperial House, being the "nomen" Iulius that of Caius Iulius Caesar, passed by adoption to Augustus and to the whole Iulia Claudia Dynasty.

Major Tom said...

Caius Iulius Polybius was a freedman surely. These remains, 8 males and 4 females, were examinated many years ago. The 6 younger, boys and girls, have the same mothernal ancestry, maybe were brothers, but the woman that embraces the younger boys isn't their mother. Adult woman remains are not related with boys and girls. Maybe she was already died and her husband had another woman.
The greatest girl was pregnant, for this her relatives were nearby her all.
The other ones can be the relatives of the girl's husband and some slave.

Kepler said...

I also would like to know the answer to Maju's question. How did they get that DNA?

Ponto said...

Some of those "bodies" that you see casts of actually contain skeletons that was within the mould made of their bodies prior to their soft tissues being cremated and bacteria/enzymes consuming the rest of what was left of the soft tissues.

The obvious answer is from the bones and teeth probably the teeth left behind.

Surely you don't think they fabricated the results?

Maju said...

Thanks for explaining, Ponto.

I did not think they fabricated the results but was puzzled because I did not know there was anything left inside the casts. The matheral and methods sections are also interesting.