How to test DNA

I believe that many people will conduct various examinations in their daily lives. Some are to check their physical condition, but some are to check their blood relationship. For example, DNA testing is a kind of paternity test. Many people know what DNA testing is, but how many people know how to test DNA? If you don’t know much about this kind of thing, then let’s learn about it through the following article.

Parentage testing, also known as paternity testing and paternity testing, is a forensic live identification based on Mendel's law of segregation, applying the theories and techniques of medicine, biology and genetics to determine whether there is a biological relationship between controversial parents and children.

Paternity testing is often requested in the following situations:

1. Premarital pregnancy or family disputes lead to suspicion that the child is not the biological child;

2. Identify long-lost family members;

3. Inheritance of property requires confirmation of biological relationship, or identification of the biological father of a test-tube baby;

4. Suspect that the hospital transferred the wrong newborn baby;

5. Suspected of circumventing the family planning policy by adopting one's own children or giving the extra children to others for upbringing;

6. Immigration notarization needs to confirm whether the applicant has a biological relationship with someone.

Methods of paternity testing:

1. Traditional paternity testing involves blood typing. It can usually be done on children over 6 months old and requires a large amount of blood sample. This method is cumbersome, sampling is painful and has a high error rate. Traditional blood typing is useful to a certain extent, but paternity testing cannot be done based on blood type.

2. DNA paternity test. DNA paternity testing is done by sampling any tissue of the human body (such as oral epithelial cell sampling) and can also be performed before the child is born. This method is the most accurate paternity test currently available - with an accuracy rate of up to 99.99999%, and is sophisticated, simple, fast, economical and practical. According to the practice of paternity testing at home and abroad, the relative chance of paternity (RCP) is that when the RCP value is greater than 99.73%, it can be assumed that the father and the child have a biological relationship.

3. SNP detection. Currently, DNA paternity testing uses repetitive base sequences in the human genome (STR as the second-generation molecular marker) and PCR technology to identify individuals, but STR has great limitations. SNP is the third-generation molecular marker technology and is the future development direction. The identification of bodies in the 911 incident in the United States used this technology.

The cost and time required for paternity testing

At present, the charging standard for DNA paternity testing is approximately RMB 3,500-5,000 per case for a family of less than three people. Generally, the test results can be obtained after two weeks. If there is a special need, the test conclusion can be obtained within three days.