Friday, July 21, 2017

DNA - Protocogotas (Esparza et al, 2017)

Hat tip Bernard and Davidski

This triple burial dates to early Proto-Cogotas, sometime between 1918 and 1772 B.C.  The two women and unborn baby were buried atop a mattress, pillows or other organic material that decomposed, allowing rotation of the bones.

LTB-03 was a young woman who died while she was at full-term pregnancy or in labor with LTB-01, also a girl.  The nuclear and mitochondrial DNA further demonstrate this relationship beyond all doubt.  The older woman was not maternally related, but considering the nuclear DNA, the possibility of a paternal aunt or grandmother was not excluded.  (surprising that it's inconclusive)

Esparza et al highlight the importance of DNA in determining relationships of the past.  Before DNA was conducted, it had been thought that the elder woman was a man due to the robustness of the cranium and to the (seemingly) diagnostic posture; and that this was a small nuclear family that died under unfortunate and contemporary settings.  However, further osteological analysis of the cranial and post-cranial remains started to sow doubt about the 'man', and DNA finally revealed that she was a woman of uncertain relationship.

Triple burial from Fig 2.  (Esparza et al, 2017)
In past generations, many touching assumptions seemed reasonable of Early Bronze Age burials:  A man and woman in a pit grave were husband and wife.  A woman embracing a small child was the child's biological mother.  They weren't bad assumptions, most are likely correct; but they are not facts.  Obviously, DNA has excluded certain relationships in this burial.

Before getting to the gender identity of LTB-02, quick background. Esparza et al, 2012b previously came up with a theory for the gross lack of Cogotas Horizon burials in Central Spain, attributing them to exposure or something.  For the few discovered burials, when they did occur, they were exceedingly those of females.  They essentially make a case that Cogotas people dealt with taboo deaths, such as a woman dying in labor, differently from the general population.  In other words, this burial from Los Tolmas might have had been associated with a taboo death.  They make a compelling comparison to the treatment of taboo deaths of pregnant women in colonial Ghana.

Next, they offer some alternative scenarios for the relationship between these women from discussions at a recent workshop.  One proposal was that the elder woman was a mid-wife, who for whatever reason, was volunteered into this situation.  Given the lateness of the pregnancy, and obviously the poor outcome, it seems possible the mid-wife found herself in an inescapable cloud of superstition.  It's also possible that the pregger died before labor and some unfortunate, lower-class soul got the honor to deliver her lady's child in the next world. 

Given the manliness of the elder woman and the orientation of the burial, the conversation drifted toward 'gender identity'.  But in my view the circumstances surrounding this burial make more sense when focused on the tragedy of a very pregnant woman dying unexpectedly. 

Protocogotas is the tail end of Bell Beaker in this region, so their genomes might offer a fuller picture of the Mesetan ethnicies from the previous period.

"Familiar Kinship?  Palaeogenetic and Isotopic Evidence from a Triple Burial of the Cogotas I Archaeological Culture (Bronze Age, Iberian Peninsula)"
"Summary. This paper examines the identification of kinship relations in
archaeological multiple burials and advocates the application of different
methods and lines of research to clarify such issues in relation to funerary
practices. Recognizing family relationships – an important task in research on
prehistoric societies – is especially complicated and interpretations have often
been made without an adequate empirical basis. Bioarchaeological, isotopic
and DNA analyses applied to the triple burial of Los Tolmos (Cogotas I
archaeological culture, Iberian Bronze Age) have provided direct information
on this issue. In this respect, the new results also imply the need to consider gender
constructs in greater depth and to be more open-minded towards other forms of
relationship in the past beyond the traditional heteronormative nuclear family." 

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