The History Of DNA Testing
Identifying DNA is one of the most critical discoveries made in medicine and science. DNA testing has opened the way for biological identification. The development of accurate methods of genetic testing took decades before the accuracy of DNA testing became a reality.
The first step to DNA testing was blood typing. In the 1920s, scientists discovered that the four blood groups- A, AB, B, and O- were genetically inherited. They discovered specific proteins that enabled them to predict the blood type of a child based one the blood types of the parents. Blood typing was an important discovery that made procedures like blood transfusion and organ transplant easier. It may have been a big step in genetic testing, but blood typing was not a conclusive method to determine the paternity of a child as it is only 30% accurate.
Serological testing was then developed in the 1930s, where specific antigens found in body tissues were discovered to make the procedure of blood typing more conclusive. However, this method was also not accurate enough to test biological relationships between people.
HLA testing was then discovered in the 1970s. A certain protein that was present throughout the body was the focus of these procedures, where the white blood cells had the highest concentration of this protein. The protein analyzed varies greatly between people who are not related, and the method is 90% accurate, which was good enough for genetic testing. However, it requires a relatively large blood sample and takes a long time to get the results.
In the 1980s, RFLP DNA testing became the first genetic test that used DNA. This procedure involves the DNA protein being sectioned and labeled by enzymes. During a paternity test, a child’s DNA should be a 50/50 match of the father’s and mother’s DNA, except in the case of mutations. This method of testing makes it easy to determine if the variations are due to mutations, which was impossible to know using the methods of the earlier decades. RFLP testing is 99.99% accurate, but is not a frequently used method for genetic testing. This is because it needs a blood sample and the test takes a while to produce the results.
PCR DNA tests replaced the RFLP procedure in the ’90s as a simple cheek swab is all that was needed to perform a test. The results also take just one day to be processed. This procedure targets exclusive sections in DNA in order to determine the differences between the samples being tested.
Scientists then developed the SNP method in the early 2000s which focuses on testing specific genetic markers. This was the foundation for the testing of genetic diseases and ancestry. From 2010, Next Generation Sequencing became the newest technique in DNA testing. It focuses on generating a DNA sequence that is based on the arrangement of the letters in a DNA sample. This method collects all the genetic information generated to create a DNA profile using a computer program.
Currently, DNA tests are more accurate, available and affordable. Previously, they were mainly used in court cases as evidence. Now, anyone can purchase a home DNA test kit to find out details on their ancestry, health, and paternity.