I actually did an ancestral DNA test to find out where my family could possibly be from in Africa. So I do have an idea about this genetic heritage analysis and what to expect. It is very surprising especially because coming from a background with grandparents from the caribbean islands of Jamaica, Antigua and Montserrat, that is the most history you know about your family. Many records were destroyed or not created about in the african-american/ caribbean community. This leads me to the interest of this topic and how I could gain so much tests like these.
As I mentioned in the introduction, I could have this test performed by a company that focuses on genetic heritage by collecting samples of patients that personally provide the samples and send them in. Another way would have a doctor or a genetic counselor perform this analysis. From the National Society of Genetic Counselors they defined what a genetic counselor as having understanding as well as modification of the psychological and medical as well as the connections to familiar “genetic contributions to disease” and this includes three processes. The first being: interpreting the history of family medical issues in order to determine if there are higher risks for an individual in obtaining the disease or having a disease recur. The second, educating on the prevention of diseases, the management of these diseases, the testing and resources available for an individual and lastly the inheritance of an individual. The last process is the purpose of encouraging individuals on the options and/ or the adaptations in order to have an individual make informed decisions.
I learned from the University of Rochester Medical Center’s Health Encyclopedia that biochemical genetic testing is available to be done. This is important because it focuses in the proteins and enzymes within the body and can determine if something is not right. If these proteins and/ or enzymes are not functioning properly, it can cause defects in newborn babies at birth. These defects determine the functionality of the metabolism. The problems that affect this area are called “inborn errors of metabolism”. Many issues involving these metabolism enzymes can be analyzed and when an issue is found the genetic testing of a specific gene can be tested. Specific genetic testing is needed though for specific disorders, as even these tests can not always find all possible mutations.
For genetic analysis, there are three general methods which are cytogenetic testing, biochemical testing and molecular testing. As for cytogenetic testing, this type of testing focuses on looking at chromosomes to determine if there is any abnormalities structurally. The most commonly tested are white blood cells, but cells from amniotic fluid and bone marrow can also be used to test. The cell are cultured and put on a plate, which is then stained. This allows for the bands on the chromosomes to be seen, and then the process, fluorescent in situ hybridization (FISH) can be done. This process finds the issues in chromosomes by painting them with fluorescent molecules. This process can identify deletions, insertions, applications and translocations. This is why this process is mostly used when testing syndromes involving babies, children and adolescents that have chromosome deletions. The second method, biochemical testing, I mentioned in the last paragraph. The problems tested are known as “inborn errors of metabolism” and mess up the metabolism. This method focuses on testing a protein rather than the gene of a disorder or disease. These tests can look at the activity of an enzyme, the amount of metabolites, and the amount of protein or the size of a protein. Lastly, the third method is molecular testing. Molecular testing involves four methods within its own testing category. First, the direct analysis of DNA, which is used when a biochemical test is not able to be completed, but the gene sequence is available. The molecular test can use any tissue sample and analysis can be performed through polymerase chain reaction (PCR), which amplifies segments of the DNA being specifically looked at. This happens by repeating denaturation, annealing and elongation. Denaturation means the separation of DNA through heat, annealing means the binding of primers of the specific segment from the parental strand, and elongation meaning the addition to the primer sequences in order to make a copy of the DNA sequence. But hybridization or direct sequencing can also be used to perform a direct analysis. The second method of molecular testing is comparative genomic hybridization (CGH) or chromosomal microarray analysis (CMA) which measures the amounts of fluorescently marked DNA compared to the regular DNA used for reference. CGH finds minor deletions or duplicates. The third method is DNA microarray analysis also known as DNA chip analysis, gene analysis, or genome analysis. It is for figuring out gene expression. mRNA binds to a template of DNA from a gene where it came from. A program finds the number of mRNA that is fixed to the sites on a array, which has a lot of DNA templates. The last method is protein microarray analysis, which this process is to determine how much protein is in a tissue samples. Just like DNA microarray analysis, it uses proteins that have been marked to be measured next to a reference. If a protein is missing, prest, if the level is increased or decreased, it can be a sign of disease. This is known as a biomarker.
These tests can all help determine whether people are at risk or their future offspring could be at risk for a disease or disorder. As for ethnicity, I mentioned in the introduction that it was really eye opening and important test for me. Through genetic testing we can see how people from the same ethnic background have similarities in what risks and what genes are more common in those communities. This genetic analysis can be very helpful for families looking to find more about their pasts as well families looking to find more about their futures.