Along with other researchers at the Wellcome Trust Sanger Institute, Professor Young Seok Ju of the Graduate School of Medical Science and Engineering published an article in the scientific journal Nature regarding findings about cell mutations in the earliest stages of human life. Titled “Somatic Mutations Reveal Asymmetric Cellular Dynamics in the Early Human Embryo”, the article was published on March 22.
Understanding what occurs during very early human development has been one of researchers’ perennial quests. As their Nature article specifies, researchers at the Wellcome Trust Sanger Institute have reached further lengths in this quest. The researchers discovered a collection of mutations that occur during the early embryonic stages and were then able to use this knowledge to uncover that, at the two-cell stage of the human embryo, one of the cells gains dominance and ends up accounting for 70 percent of adult body tissues, while the other cell has a more submissive role.
The researchers collected and analysed blood samples from 279 individuals with breast cancer. Since the number of mutations that arise during early development stages is relatively miniscule compared to the number of genetic variations inherited by an individual, the researchers were able to pinpoint and discover 163 mutations that surface during the early phases. As Professor Ju put it, “[The process is] like finding a needle in a haystack.”
Knowing which mutations occurred in the first, second, and third divisions of the fertilised egg, the researchers were able to statistically analyse the data and compute the proportion of adult cells that originated from each of the first two embryonic cells. They validated the proportions by looking at cancer tumour samples removed from the breast cancer patients. Since tumours develop from a single mutant cell, a proposed mutation should be present in all of the cancer cells in the tumour or in none. The researchers were also able to determine that these proportions were applicable not only to blood cells, but also to other cells such as lymph and breast cells.
|Contributions to the final cell pool by the cells from each division|