Month: August 2018

Child Born 90,000 Years ago had Neanderthal Mother and Denisovan Father

Posted on by childhoodbioarchaeology

Breaking news about an astonishing find of a child is hitting international news. The paper presents the genome of ‘Denisova 11’, who is represented by a small bone fragment from Denisova Cave in Russia. The authors found that the individual was a girl of at least 13 years of age and has a Neanderthal mother and a Denisovan father.

Interestingly, the authors argue that this type of mixed-breeding between Late Pleistocene hominin groups must have been common, given this finding of a Neanderthal–Denisovan offspring among a very small number of archaic specimens genetically analysed to date.

Screen Shot 2018-08-23 at 7.03.33 PM.pngDrawing of a Neandertal mother and a Denisovan father with their child, a girl, at Denisova Cave in Russia (Credit: Petra Korlević)

Screen Shot 2018-08-23 at 6.41.26 PM.pngThe bone fragment ‘Denisova 11′ from several angles  (photo taken by Tom Higham)

I was interested in the age-at-death estimation carried out from the analyses of cortical bone thickness. Although presented as fact that this individual was a “child” in the news with quotes from the main authors, it rightly states in the paper’s supplementary data that there are various problems with estimating the age-at-death of this specimen. They argue that the bone fragment may be from a femur, tibia or humerus because of its thickness of 8.4mms. However, archaic hominins were likely more robust, so it could be that this may have been from a smaller bone from a robust adult. So really they can’t actually say that it is a child, but that she was at least 13 years old. However, it goes without saying that regardless of this ‘child’s’ age, this is a very important finding.

 

Skull trauma in children indicates violent pre-Hispanic Canary Island societies

Posted on by childhoodbioarchaeology

There is a romanticised view that pre-Hispanic societies from the Canary Islands lived in a ‘paradise on earth’ without violence and conflict. However, recent work by anthropologists has shown that there is evidence for intentional trauma in adults from pre-Hispanic sites suggesting inter-personal violence. A recently published paper has found that the young were not spared this violence, with a high number of children from the island of Gran Canaria with skull trauma. This is significant as there is generally less evidence for violence in children compared with adults from archaeological contexts.

Screen Shot 2018-08-09 at 6.13.49 PM.png

Figure 1: A seven year old child from Guayadeque, Gran Canaria, with blunt force trauma occurring around the time of death (from Velasco-Vázquez et al. 2018).

 

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Figure 2. Areas of the skull that showed traumatic injury (from Velasco-Vázquez et al 2018).

The infants and children analysed in this research are from sites that cover an expansive part of the pre-Hispanic occupation of Gran Canaria from the 6th to 15th century CE. The authors studied a total of 65 infants and children looking to identify any sharp force trauma, puncture injuries, and blunt force trauma on the skull. Fourteen children suffered from craniofacial injuries, all of which were blunt force trauma, and two of these children have evidence that this trauma resulted in their death (e.g. Figure 1). Most of the skeletal trauma occurred on the face or forehead, a similar pattern observed in adult studies of trauma in these populations (Figure 2).

Children could have been engaged as actors in this violence as well as the victims. Although early scholars painted the Canary Islands as a peaceful and bountiful paradise, ignoring  evidence for social inequality and conflict, there is archaeological evidence for marked social hierarchy and resource depletion in this insular community, which likely led to significant social unrest.

The late mediaeval agrarian crisis and the Black Death revealed through stressed childhoods

Posted on by childhoodbioarchaeology

Looking at the teeth of adults can tell us a lot about early life-histories and unlock the secrets of the living conditions of past communities. An open access study published in the International Journal of Paleopathology aimed to give insight into the environmental and social changes seen in medieval Denmark, a time associated with the late medieval agrarian crisis and the mid-14th century Black Death epidemic.

Screen Shot 2017-04-02 at 6.35.23 pmThe Dance of Death or Danse Macabre, a common painting motif in the late medieval period inspired by the Black Death.

The authors used microscopic techniques to measure instances of stress in the teeth which form as the result of infection and/or poor nutrition. Teeth are especially useful for this analysis of stress as enamel forms at regular periodicity and permanent irregularities are formed when there is growth disruption from a stressful episode. Enamel growth lines visible on the tooth surface (known as perikymata) can be seen internally, and when these lines are pronounced (accentuated striae of Retzius or AS), these are associated with growth disruption. This type of analysis is especially useful as it is becoming recognised that assessing enamel defects with the naked eye is subjective, resulting in inter-observer error in quantifying these defects.

Screen Shot 2017-04-02 at 7.07.23 pm.pngMandibular canine with an example of an accentuated striae of Retzius (AS) highlighted by A (red arrows). Figure from Gamble et al. 2017.

The sample (n=70) used in this research was from the rural cemetery of Sejet and the urban cemetery of Ole Wormsgade, near the mediaeval market town of Horsens, dating from between mid-12th and mid-16th centuries.

Results showed sex differences in survivorship and stress experience. In males more stress is associated with reduced survivorship and in females more stress is associated with increased survivorship. These results are supported by previous studies investigating enamel defects and mortality in mediaeval England (e.g. De Witte 2010), which have been interpreted in the context that stress will have an adverse impact on later life health and in particular on males. Or, the authors argue, cultural factors resulting in different treatment of males and females may be a factor to explain these results.

It should be noted that the individuals used in this study survived past childhood so are not necessarily representative of the frailer individuals who died prematurely. The authors argue that “the late medieval agrarian crisis in association with episodes such as the Great Bovine Pestilence and consequent periods of famine may have interacted in a complex fashion with individual frailty for the populations in this study. Evidence points to increased morbidity and mortality prior to Black Death in England, along with selectivity in response to pre-existing health conditions as part of the Black Death epidemic. It is possible that less frail individuals who survived more stress events were able to mount a stronger immune response to pathogens later in life, thus conferring an advantage that would contribute to greater longevity.”

I wonder if further work done on AS in deciduous teeth (from the non-survivors) that form in-utero and during infancy could tease apart some of these interpretations of frailty and sex of the survivors in this study.

DeWitte, S. N. (2010). Sex Differentials in Frailty in Medieval England. American Journal of Physical Anthropology, 143 (2): 285–297.