Genetics testing has been performed for about 100 years. The principles of the inheritance of genetics were discovered in the mid-19th century by Gregor Mendel. Blood sampling became the dominant method for genetics testing in the 1920s to the 1970s. Since the 1980s, DNA testing has assisted doctors in screening for genetic conditions. DNA analysis also provides almost irrefutable proof of fatherhood
A needle for gathering a genetic sample.
History of Genetics
Science gives credit for the establishment of genetics to Gregor Mendel and his work on the hereditary characteristics of pea plants in "Experiments with Plant Hybrids," according to AccessExcellence. Mendel's work existed for several decades before the scientific world accepted his theories on heredity. He showed that traits are either dominant or recessive and are passed down intact, not combined into a hybrid trait.
Blood Tests, 1920's -1960's
While Mendel proved that traits were inherited in the 1860s, medical science did not discover that blood came in different types until the early 20th century. Because one can determine a person's exact blood type, doctor's believed that they could ascertain a person's likely father based on similar blood types, according to DNA Diagnostics Center. Unfortunately, any single blood type can be formed by several different blood types, and the accuracy of blood testing to determine parentage is around 30 percent.
In the late 195's scientists realized they could also test newborns for inherited diseases, claims Science Progress. Phenylketonuria (PKU), which causes mental retardation, was the first disease to be widely tested for in newborns. Once identified, the disorder could be treated through a strict diet.
1970s
Blood typing was the dominant trend in paternity testing until the 1970s, when scientists found that human tissue contained some highly variable proteins, according to DNA Diagnostics Center. The protein "human leukocyte antigen" (HLA) occurs only in white blood cells, and the type of HLA varies drastically from person to person. Because of this great variance, geneticists realized that the chance of two people sharing the same type of HLA is rather low. The accuracy of this test hovers around 80 percent.
According to Science Progress, the medical community started testing for two new diseases during the 1970s: Tay-Sachs and sickle cell anemia. Both diseases were considered racially biased in that certain ethnicities had much higher rates of the diseases. Tay-Sachs is predominantly a "Jewish" disease and sickle cell anemia an "African American" disease. Tay-Sachs is a fatal disorder; sickle cell disease is not curable but can be treated. People who might be carriers of either disorder are urged to be tested before having children.
Modern Testing, 1980s--Present
James Watson and Francis Crick presented the discovery of the genetic blueprint to the human body, DNA, to world in April 1953. However, DNA testing for paternity and diseases did not become economically viable until the 1980s. Scientists learned that they could compare certain unique parts of DNA to establish an almost irrefutable link to genetic disorders and family members. DNA can prove a genetic link at numbers as close to 100 percent as possible. DNA can also now be used to identify missing or altered genes that cause conditions like Huntington disease, a neurological disorder, and breast cancer according to Science Progress.
Function
DNA paternity testing is a critically important procedure for many mothers, according to the American Pregnancy Association. The courts usually accept DNA testing as definitive prove of fatherhood. Proof of a biological relationship can gain a parent access to child support payments and other social security resources of the father.
The use of genetics testing for inherited disease depends on the results of the test. Some diseases like PKU can be easily screened and treated for, but not conditions that require repairing genes or cancer. According to Science Progress, except for the well-studied conditions, genetics testing is mostly used to allow individuals and families to prepare for the onset of a disease later in life.
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