To be able to specify the age of the suspect from the blood streaks left in the crime scene

A criminal is identified from blood stains and hair other than the victim left in the crime scene by DNA appraisal ... ... Although it is a development that is likely to be in a drama such as a detective story or a criminal matter, in reality, the suspect is identified It is difficult to say that 'DNA is the deciding factor of arrest!' Unless it is being compared with the DNA contained in the database in the case that DNA samples can be collected, or by pre-surgery.

DNAFrom the type of, for example, "If the criminal is red hair, white men in their thirties in height and obesity type, and eyes are green in color", it may be useful for investigation considerably, but at the momentGenotypeAppear as a trait withinPhenotypeThere seems to be only the color of the eye that can be specified with accuracy that can be proof. In Japan where most of the population has a brown eyes, it may be said that it will not become a clue even if you know "the eyes of the criminal is brown".

According to a new test method developed by Dutch biologists, it seems possible to identify the age group of the suspect from the blood.

Details are as below.Your Blood Holds Clues to Your Birthday - ScienceNOW

As a method of identifying the age of a person from the blood appraisal so farMitochondriaAtDNA damageYaShortening telomereAlthough methods have been proposed as clues to these methods, these methods have low precision and many technical problems, so they are not practical at the scene of forensic medicine.

As a biochemical method, bone, teeth, ligament (gutta) etcAspartic acidAlthough it is necessary to estimate age from the accumulation amount of bones and teeth, etc., since it is necessary to destroy and analyze bone and tooth samples and it is useless in samples where biological decomposition advanced, for example " It may be used only in a unique case such as the criminal's teeth broke when resisting and samples of fresh teeth remained on the scene of the crime. "

In RotterdamErasmus Medical CenterDr. Manfred Kayser, a forensic scientist specializing in molecular biology atlymphocytesIt is a kind ofT cellsWe have developed a method to identify the age group of people from blood focusing on the nature of human beings. Thesis isCurrent BiologyIt is published in the magazine.

It is an immune cellT cellsIs struggling day by day with the bacteria which invaded the human body, but this T cell cuts its own DNA with chokichoki in the process of growing and connects here and then sorts it according to various pathogens We design cell surface receptors. This is called reconstitution of DNA, but at this time unnecessary DNA for surplus T cells will create a circle and drift through the blood. Kayser and colleagues thought that it would be possible to identify the age of the owner of the blood by measuring the amount of "kas" (fragment) in this DNA.

Since the number of newly created T cells decreases with age, the amount of T cell DNA fragments present in the blood also decreases with age. Dr. Kayser and colleagues found a strong correlation between the amount of fragments and age by analyzing 200 blood samples from weeks after birth to 80 years of age. Markers designed to bind to this fragment (fluorescent DNA) allow you to measure the amount of fragments in a matter of hours, so that you can identify your age with plus or minus 9 years of age accuracy. The same precision was obtained even for blood samples which passed one and a half years after collection.

The accuracy of plus or minus 9 years is that the age of the suspect can be narrowed down to the range of "21 to 39 years old", "32 to 50 years old", "55 to 73 years old", for example. Are the ranges too wide? I think, but,Leiden University HospitalDr. Peter de Knijff, president of Forensic Research Institute, said, "This is enough to classify the suspects into specific generations, which would be very useful for the police. We can narrow down the width of the person to a certain extent and this is precise with the current technology. "

Dr. Kayser et al.BiomarkerIt seems that it aims at further improving age-specific accuracy by combining with the inspection of.