A team of researchers identified the first ever prehistoric person with mosaic Turner syndrome and other genetic disorders by developing a new technique for measuring the number of chromosomes in ancient genomes.
What Can We Know From Ancient DNA Samples?
Most cells in the human body contain 23 pairs of DNA molecules called chromosomes. From this set, one pair consists of sex chromosomes, which are either XX (female) or XY (male).
There are cases, however, when a person's cells have an extra or missing chromosome in a condition known as 'aneuploid.'. If this happens in the sex chromosomes, a few differences can be observed, such as delayed development or changes in height around puberty.
Ancient DNA has been a valuable tool in studying genetic and evolutionary history and providing detailed profiles of the lives of prehistoric individuals. However, ancient DNA samples can erode over time and be contaminated by DNA from other old samples or people who handled them. This makes it challenging for scientists to capture the differences in the number of sex chromosomes accurately.
READ ALSO: Comprehensive Primate Genomic Catalog Unveils Insights into Human Evolution and Disease
New Approach to Studying Ancient Genomes
To solve this problem, researchers at the Francis Crick Institute, in collaboration with the University of Oxford, University of York, and Oxford Archaeology, developed a computational method that can pick up more variation in sex chromosomes. The new technique was used in analyzing ancient DNA from a large dataset of individuals gathered as part of the Thousand Ancient British Genomes project across British history.
The researchers identified six individuals with aneuploidies across five sites in Oxford, Somerset, Lincoln, and Yorkshire. The prehistoric individuals lived across a range of periods, from the Iron Age about 2,500 years ago to the Post-Medieval Period about 250 years ago.
The identified individuals had sex chromosomes that fell outside the typical XX or XY categories. All of them were buried according to their social customs, although no possessions were found with them to provide more information about their lives.
The three individuals with Klinefelter syndrome lived across various periods but shared some similarities. All of them were slightly taller than average and demonstrated signs of delayed development in puberty.
Meanwhile, the investigation of bones allowed the research team to discover that the first prehistoric person with mosaic Turner syndrome lived about 2,500 years ago. It was unlikely that this person had gone through puberty and started menstruation despite their estimated age of 18-22.
The new method has also led the experts to conclude that the earliest known person to have Jacob's syndrome came from the Early Medieval Period. It also helped them identify an infant from the Iron Age who showed signs of Down's Syndrome.
It was hard to see a complete picture of how these prehistoric people lived and interacted within their society since they were not found with possessions or in unusual graves. Still, the study offered new insights into how perceptions of gender identity have evolved.
RELATED ARTICLE: Genome Sequencing Traces the Lineage of Early Humans; Is It Time to Reconsider Our Origin?
Check out more news and information on Genome in Science Times.
