1980s - DNA Testing Using RFLP Technique
In the mid 1980s, a technique was developed called restriction fragment length polymorphism (RFLP, pronounced "rif-lip"). This technique became the first genetic test using DNA. Like HLA and blood proteins, DNA is genetically inherited from both parents. However, sections of DNA are highly variable and more unique than HLA and blood proteins, and it is found in every part of the body. These attributes make DNA ideal for identifying biological relationships.
RFLP allows scientists to cut out the unique sections of the DNA, which is extracted from blood samples. For paternity testing, these unique sections of the parents and child are compared. Half of the child's DNA should match the mother's DNA, and half should match the father's DNA if they are biologically related.
Sometimes during this procedure, the child's DNA will not appear to match either parent's DNA, possibly caused by genetic mutations. When this occurs, scientists will perform statistical analysis to determine the possibilities of mutation and biological relationship between family members.
Because RFLP is applied to DNA testing, this procedure yields highly conclusive results, typically with a power of exclusion higher than 99.99%. However, this technique is not performed frequently today because, like HLA testing, RFLP requires a large blood sample and a longer turnaround time.
Introduction to DNA Testing History
1920s >> Blood Typing
1930s >> Serological Testing
1970s >> HLA Testing
1980s >> DNA Testing Using RFLP Technique
1990s >> DNA Testing Using PCR Technology