Ancient DNA Unveils Sex-Chromosome Syndromes From 5,000 Years Ago

The earliest cases of sex-chromosome syndromes have been discovered by researchers, suggesting that individuals with extra or missing chromosomes existed around 5,000 years ago. A study published in Communications Biology highlights that people with genetic syndromes have been a part of human societies throughout history, often exhibiting distinct physical characteristics and behaviors.

Kyriaki Anastasiadou and the research team from the Francis Crick Institute in London utilized DNA sequencing to identify ancient individuals with atypical numbers of chromosomes. They found an infant with Down syndrome, characterized by an extra copy of chromosome 21, living approximately 5,000 years ago. Additionally, they identified the first prehistoric individual with Turner syndrome, a female who had only one complete X chromosome, from around 2,500 years ago in Somerset, UK.

Another discovery was a male with an extra Y chromosome, known as Jacob’s syndrome, who lived around 1,100 years ago during the early Medieval Period. The researchers also found three ancient males from different time periods with an extra X chromosome, a condition called Klinefelter syndrome, which is associated with increased height and broader hips.

Surprisingly, there was no evidence to suggest that these individuals were treated differently in terms of burial or cause of death. DNA samples were derived from various skeletal remains, including teeth, skull, jaw, and ear bones. A computational tool was employed to calculate the number of DNA fragments from sex chromosomes, allowing the researchers to determine the presence and ratio of X and Y chromosomes in each individual.