A new analysis of 66 early human remains has revealed an incredible 75 cases of skeletal abnormalities, from bent thighs…
A new analysis of 66 early human remains has revealed an incredible 75 cases of skeletal abnormalities, from bent thighs and armbones to abdominal jaws, dwarf and a swollen brain that conforms to hydrocephalus, a condition characterized by fluid build-up in the skull.
This surprisingly high birth rate is likely to be representative of ancient populations as a whole, writes paleoantropologist Erik Trinkaus at Washington University in St. Petersburg. Louis in a new paper published in the National Academy of Process of Sciences . As he tells Science the journal Michael Price, the odds are to reveal so many discrepancies in such a small sample size simply “randomly small”.
Trinkaus argues instead that the skeletons dating back to about 200,000 years ago and upgraded in regions as far as China, the Czech Republic, Italy and Israel testify to the widespread cultural and environmental pressure that our prefessors occur.
Maybe pregnant mothers failed to follow a healthy diet, leaving their offspring susceptible to skeletal disorders like rickets. Perhaps individuals who showed abnormalities were given more elaborate funerals, giving up the chances of their conservation and future rediscovered. [Andrew McGerson says that Trinkaus has not found evidence of different funerals used for them with or without defects.] It is also possible that life as a hunter collector was just irreversibly challenging: As the study notes, ” The abundance of developmental abnormalities in Pleistocene humans may have improved with the generally high stress levels revealed among these native populations. “
However, the most likely culprit is unreasonable inbreeding among old populations, according to Hallie Buckley, a bioarchaeologist at New Zealand University in Otago that was not involved in the new study. Given the limited size and relative isolation of early human societies, as evidenced by the low genetic diversity seen in previous studies of old DNA, Buckley Price says that “this seems to be the most likely explanation. “
Some of the abnormalities as Trinkaus discovered are hereditary conditions, making them more likely to manifest among the offspring of closely related individuals. Many continue to this day, explains the study, which appears in the latest human specimens as “unusual but not exceptional” conditions. Others are “extremely rare” in modern populations and are therefore unlikely to appear in the fossil record.
Trinkaus found that the chance to identify more typical abnormalities among the early populations was about five percent based on comparisons with modern humans. The chances of identifying one of the rare abnormalities were as low as 0.0001
“The chances of finding them in combination or collectively as evidence in each set of residues so far discovered and reliably dated are astronomical,” concludes Masterson for Cosmos .
The presence of deformities in ancient remains is not surprising in itself, but adds, but becomes significant instead of the pure number seen in only 66 sets of remains.
Still, Siân Halcrow, a bioarchaeologist at the University of Otago, who was not involved in the study, Science ‘s price that extrapolates estimates of abnormality incidence among early humans by drawing similar figures in modern populations is problematic . A better approach would be to compare the old prices that are clear across the sample with data from prehistoric or early historical populations – a difficult task complicated by the fact that such data pools do not actually exist.
Trinkaus could not directly identify the causes of the 75 abnormalities identified, but as he concluded in the study, there were probably a number of factors – not only once: “A significant number of these abnormalities reflect abnormal or divergent developmental processes, either as a result of genetic variants that change development processes or as products of environmental or behavioral stress patterns that change expected development patterns. “