A research group led by Professor Keiji Tamaki of the Graduate School of Medicine, Kyoto University has used the DNA of intraoral cells to determine the blood relationship between two people, which could only be determined by parents and siblings (children of cousins). ) Developed a new DNA testing method.It is expected to improve the accuracy of identity verification in the event of a large-scale disaster.
Human genetic information is conserved by a sequence of substances called "bases" in the DNA strand.Since the arrangement of these bases differs from person to person, detecting this difference as a DNA type and identifying an individual is called "DNA test", and in particular, determining the presence or absence of a blood relationship between individuals by DNA test is "blood relationship". Called "appraisal".
DNA is folded into small pieces and transmitted from parent to child as chromosomes.People who are closely related to each other, such as parents, children, and siblings, share more chromosomes than people who are far from each other or others. Become.However, only parents and siblings can be completely judged by the current appraisal method.
This research group succeeded in detecting a small amount of chromosome sharing in distant blood relatives using an index called "chromosome sharing index (ICS)" that was originally devised.With this method, regardless of gender, there is a 99.9% or more chance of distinguishing from other people, not only close relationships like siblings, but also distant blood relationships such as cousins, one person and his cousin's child, and about 94% of cousins. It is possible.
Since the judgment principle of this appraisal method is mainly a computer-based examination, a DNA test was conducted with the cooperation of people with various blood relationships such as actual siblings, and as a result of verifying whether the blood relationship can be correctly determined. I was able to correctly judge all blood relationships such as siblings, cousins, and second cousins.
In the future, we plan to increase the number of samples and verify the accuracy.In addition, although DNA extracted from cells in the oral cavity was used this time, the DNA is often broken in the nails, teeth, and bones collected from the body for the purpose of identity verification, and there is a possibility that the DNA type cannot be accurately inspected. be.Therefore, it is said that research will be continued so that judgments can be made reliably even from such samples.The results of this research were published in the American scientific journal "PLOS ONE".
