This post is a gripe at a new paper (which I largely agree with) (*update 1* -I've changed my mind-I'll put in the next post) called
"The Known Knowns and Known Unknowns" which briefly discusses the odd presence of mitochondrial "haplogroup H" among the people of the Mesolithic Portuguese shellmiddens. I've finally reached the maximum vomit threshold with shellmidden DNA, so please bear with me.
The progress of ancient DNA research in Europe is beginning to show that these results are indeed outliers. It was already a logical fallacy to suggest Haplogroup H was in an Iberian LGM refuge and remained there at an extremely high frequency but failed to expand to the rest of Europe and then, by-the-way, remained relatively hidden in the midst of fairly typical Neolithic farmer genomes within the region and finally went gang-busters to the Russian plain in the Early Bronze Age. But looking closer at the "modern" results from the shellmiddens and a little background on the bones (that were probably licked by half the Portuguese population) the results become even more suspect.
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| Skeletons 7 & 8 Amoreira 1933 (Jackes, |
Chandler, Sykes, Zilhão, 2005
This
important study became confirmation for the retarded notion that modern Western
Europeans are in large part maternally descended from
indigenous, Mesolithic hunter-gatherers.
Chandler's results showed that
Mesolithic Iberian maternal lineages were virtually indistinguishable
from high frequency modern ones of Western Iberia and gave credence to the theory that Iberia
was an important glacial refuge (for modern Europeans) during the Last Glacial Maxim.
I
will offer a very respectful criticism here, especially since ten years
have past, but this study becomes increasingly problematic the more you
look at it and it is the foundation for so much wasted debate. I will
say that it is critical for those interested in the genetics of Western
Europe to know the
archaeology and
conditions from these early studies.
This
research used available remains excavated between 50 to 130 years ago.
No remains tested, as I understand, were excavated at least within the
last thirty years.
Of the fifteen Mesolithic burial sites in Portugal, only half are "dated"
and "of those" half are from
shell middens.
Several are on the Rio Muge at
the mouth of the Tagus, the Sado Valley and a single Atlantic site at
Alentejo. Most of these sites were excavated beginning more than a
century ago, although intermittent work has continued in the last six
decades.
From these, Chandler describes most being from the Sado Valley, including Amoreiras (which I will pick on):
"Mesolithic
sites were primarily sampled from the Sado valley estuary [Alentejo],
including Arapouco, Vale de Romeiras, Poças de São Bento, Cabeço de Pez
and
Cabeço das Amoreiras (São Romão) (Arnaud 1989, Cunha
and Umbelino 1995-1997). The two sites sampled outside the Sado valley
were the early Mesolithic site of Toledo in coastal Estremadura (Araújo
1998) and the coastal Algarve site of Fiais (Araújo 1995-1997, Morales
and Arnaud 1990)... "
Let's
start by looking at the materials taken from
Cabeço da Amoreira [on the Sado, not similarly named site on the Muge]. Keep
in mind the quotes you are reading are concerning other anthropological
studies, not this DNA study, but will help you with context.
"The Muge
shellmiddens were found 150 years ago in 1863 by Carlos Ribeiro. Since
then, several projects in the area excavated the various sites at the
archaeological complex of the Mesolithic Muge shellmiddens. The result
was the recovery of more than 300 human skeletons. However, most of
those burials have insoluble problems of associated materials,
provenience, stratigraphy and chronology." (Bicho et al, 2013)
Also this from Diniz:
"More
recently, a 14C date from human bones put Amoreiras [in Alentejo] first
(?) occupation in the beginning of the 6th millennium cal AC and our
pottery analysis clearly show that beside Early Neolithic ceramic, Final
Neolithic pottery is also present both recovered in the same artificial
levels giving Amoreiras a chronological and cultural complexity not expected before." (Meiklejohn et al, 2009)
You
will notice that Diniz refers to the levels within the middens as
"artificial". So
in Amoreira [Alentejo] we have Early & Final Neolithic materials
within a supposed Mesolithic level, which was man made to begin with and
where intrusive burials continued for a great amount of time.
Properly
stratifying an un-contextualized find within a midden depends highly on
carbon dating to verify its "authenticity". The majority of radio
carbon dates from the middens have come from bone, which by the way,
come from individuals whose diet consisted of at least 50% shellfish.
Given
the delta between charcoal dates and bone dates in this area, its easy
to lose confidence in early C14 dates of particular materials quickly,
not that much confidence would be had in the bones of a brackish marine
life eater.
Christopher Meiklejohn address the increasingly erratic radio dates of Mesolithic remains throughout the Portuguese middens:
(Mesolithic Mescellany V20-9, 2009). Keep this in mind as you read further.
Aside from the fact that Cardial folk also used the
middens for burial (more clearly in Northeastern Iberia), the processing
of the material itself may has left numerous problems for further
scientific research.
"In the
absence of commentary on the date and possible contamination, especially
the issue of the use of paraffin in the preservation of the burials
[1865], interpretation of this and the other direct dates on Sado midden
burials should be made with considerable caution." (Meiklejohn)
Viability and Provenance of DNA extraction from Muge and Sado middens:
In general, the remains from Amoreira were neglected for anthropological study for an especially poor state of preservation
(Cunha and Cardoso, 2001).
Because of this, they were contained in
parafin, another issue. The alkalinity of the middens is an issue.
Almost all of the material from
Amoreira, Moita and Arruda were calcified in a dense matix. (Cunha and Cardoso)
The remains from
the Muge were spread across three museums, one of which caught on fire
in 1974,
causing multiple remains to become mixed. (Cunha and Cardoso) Some
of the remains excavated at Amoreira were lost after excavtion, but
some remains not from Amoreira somehow became associated with it. Cunha
and Cardoso also state (unrelated to the DNA study)
"Since
some of the material lacked labels, some radiocarbon dates were
performed in order to demonstrate their Mesolithic provenance (Cunha and
Cardoso, 2002). The human bones retrieved at Amoreira were analised in
this context."
Bear in mind that after the
provenance of the materials being handled became questionable, the
authenticity of the materials were reaffirmed through carbon dating.
They did exclude some skeletal material that came in a box
labeled "Mesolithic" but later turned out to be skeletal material from
the Iron Age that somehow became mixed in the Amoreira materials. Those
remains not calcified were easily removed from this association.
There are issues with how the bone material was cleaned in the months prior to DNA testing (unrelated to this study)
"Acetic
acid seems to be efficient in removing the calcite, however, as
secondary consequences are not fully known, we opted to study the
material as it was." (Cardoso in unrelated study)
**Update 2** After re-reading Cardoso's comment it would appear that acetic acid was not used on remains after all, being as he said, the 'secondary consequenes not being fully known'.
There are other issues with these remains. I don't want to come off like a chimpanzee on xanex, so I will leave it at that for others to study, but some of these early DNA studies from Southwest Europe and Italy need to looked at with a little more caution before we spend a lot of time debating European pre-history.
