Science & Technology, Australia (Commonwealth Union) – An international team of researchers has unveiled instances of chromosomal disorders, potentially marking the earliest known case of Edwards syndrome within prehistoric remains through the examination of ancient DNA.
In their study, the team pinpointed six instances of Down syndrome and one instance of Edwards syndrome among human populations residing in regions such as Spain, Bulgaria, Finland, and Greece dating back as far as 4,500 years before present.
The findings suggest that these individuals were accorded respectful burials, often accompanied by distinctive grave offerings, underscoring their valued status within ancient societies.
Conducted as a global collaborative effort, the research was spearheaded by Dr. Adam “Ben” Rohrlach from the University of Adelaide as the first author and Dr. Kay Prüfer from the Max Planck Institute for Evolutionary Anthropology as the senior author. The study involved scrutinizing DNA samples from approximately 10,000 ancient and pre-modern humans to detect evidence of autosomal trisomies, a genetic condition characterized by an additional copy of one of the first 22 chromosomes.
Dr. Rohrlach, a statistician affiliated with the University of Adelaide’s School of Mathematical Sciences indicated that with the utilization of a recent statistical framework, they analyzed DNA extracted from human remains spanning the Mesolithic, Neolithic, Bronze, and Iron Ages, extending to the mid-1800s and their investigation uncovered six instances of Down syndrome.
“While we expected that people with Down syndrome certainly existed in the past, this is the first time we’ve been able to reliably detect cases in ancient remains, as they can’t be confidently diagnosed by looking at the skeletal remains alone.”
Down syndrome arises when an individual possesses an additional copy of chromosome 21. Utilizing a pioneering Bayesian methodology, researchers successfully pinpointed six instances amidst tens of thousands of ancient DNA samples with precision and efficiency.
Dr. Patxuka de-Miguel-Ibáñez from the University of Alicante, who serves as the principal osteologist for the Spanish sites, pointed out that the statistical model detects when an individual harbors roughly 50 percent excess DNA originating from a specific chromosome.
“We then compared the remains of the individuals with Down syndrome for common skeletal abnormalities such as irregular bone growth, or porosity of the skull bones, which may help to identify future cases of Down syndrome when ancient DNA can’t be recovered.”
The investigation also revealed a singular instance of Edwards syndrome, an uncommon genetic condition resulting from an extra copy of chromosome 18, exhibiting more severe symptoms compared to Down syndrome. The skeletal remains displayed pronounced abnormalities in bone development, suggesting a gestational age of approximately 40 weeks at the time of demise.
All instances were identified in perinatal or infant interments, spanning diverse cultures and historical epochs.
Dr. Rohrlach. Pointed out that those interred were laid to rest in accordance with prevailing burial customs or received distinct treatment, implying recognition as valued members of their respective communities, even in death.
Professor Roberto Risch, co-author and archaeologist affiliated with The Autonomous University of Barcelona indicated that of note, they encountered the sole case of Edwards syndrome and a notable uptick in occurrences of Down syndrome among individuals hailing from the Early Iron Age in Spain. Professor Risch further pointed out that while the remains were unable definitively establish whether these infants survived beyond birth, they were among those interred within domestic dwellings or other significant structures.
“We don’t know why this happened, as most people were cremated during this time, but it appears as if they were purposefully choosing these infants for special burials.”
The findings have been officially released in the esteemed journal Nature Communications, marking a significant milestone in a comprehensive collaborative effort. This endeavor engaged scholars from the University of Adelaide, notably Dr. Adam “Ben” Rohrlach, Dr. Jonathan Tuke, and Associate Professor Bastien Llamas, alongside researchers spanning various international institutions. Among them, the Max Planck Institute for Evolutionary Anthropology in Germany played a pivotal role in data generation.
The study demonstrates the significance of evaluating ancient historic objects and data which can help indicate specific conditions and diseases that were a main focus, which can be compared to present data where it can be evaluated and determined as to why such conditions were dominant then in comparison to the present. Ancient cave drawings have helped scientists get insights into the possible bone diseases that were present at the time where individuals in the drawings with bent knees have been highlighted.
