Understanding the Different Types of DNA Testing

DNA testing is a type of genetic testing that can identify changes in genes, chromosomes, or proteins in the body. It is used to confirm or rule out if you have a genetic condition, determine your chances of developing or transmitting a genetic disorder, and look for changes in genes, chromosomes, and proteins. There are several types of DNA tests, but the three most common are Y DNA tests, autosomal DNA tests, and mitochondrial DNA tests (mtDNA tests). Prenatal testing can be used to detect mutations in the genes or chromosomes of the developing baby (fetus) during pregnancy.

It can determine the chances that your baby will be born with certain conditions that we know how to detect. If your family has a genetic history, your healthcare provider may recommend prenatal testing. Predictive and presymptomatic tests can also be used to detect mutations that increase the likelihood of developing a genetic condition later in life. These include certain types of cancer, such as breast cancer.

Your healthcare provider will collect a sample of blood, hair, skin, tissue, or amniotic fluid and send it to a laboratory. In the laboratory, technicians will look for changes in genes, chromosomes, or proteins. The test results will be sent back to your healthcare provider. Two main types of forensic DNA testing have been performed: RFLP and PCR-based tests.

RFLP testing generally requires larger amounts of DNA and the DNA should not be degraded. Crime scene evidence that is old or present in small quantities is often not suitable for RFLP testing. Hot and humid conditions can accelerate DNA degradation, making it unsuitable for RFLP in a relatively short period of time. Autosomal DNA tests analyze most of the DNA that comes from parents (the 22 pairs of chromosomes that make up autosomes).

You can determine if someone could be the biological father of your baby or child by taking a blood test or a DNA swab on the cheek. From the pattern of probes to which the amplified DNA binds, a potential type of DNA, also called a genotype, can be deduced. The invisible dot to the right of number 1 has a DNA probe for allele 1 (variation) of DQ alpha. If a match or “inclusion” is obtained, a comparison of the DNA profile is made with a population database. After collecting biological material from a crime scene or paternity investigation, DNA is first extracted from its biological source material and then measured to assess the amount of DNA recovered.

The second step is to sequence the DNA that is assigned to a protein-coding gene, which corresponds to approximately 2% of the total DNA. Any probative biological sample that has been stored dry or frozen, regardless of age, can be considered for DNA analysis. While RFLP and PCR techniques analyze DNA extracted from the nucleus of a cell, mtDNA technology analyzes DNA found in a different part of the cell, the mitochondria. Although PCR analysis sometimes allows the crime laboratory to generate a DNA profile from highly degraded tests, it is possible that blood and semen are so degraded that nuclear DNA analysis does not yield a DNA profile. However, PCR also has the incomparable advantage of powerfully increasing the amount of DNA in small samples. Autosomal DNA tests contain much more information than Y-DNA or mtDNA tests as they can reveal more about your ethnicity and who you're related to.

Finally, it's important to note that all maternal relatives (for example, a person's maternal mother or grandmother) have identical mitochondrial DNA. DNA is the material that governs the inheritance of eye color, hair color, height, bone density and many other human and animal traits.