Abstract

Although present in both the male sperm and female egg when forming the embryo, mitochondrial DNA tends to be passed solely from the egg to the embryo, hence leaving a long-lasting maternal link between mothers and their offspring. Used in many genetic ancestry and other forms of testing methods, this secures a strong evolutionary link into determining generations of genetic and other evolutionary traits that have been passed down, recently introduced, or even the formation of new mutations, also helping discover the persistence of mitochondrial disorders that may have been passed down from those who are affected or were carriers. 

Mitochondrial deoxyribonucleic acid, simply known as mitochondrial DNA, plays a significant role in researcher’s use of this DNA to explore the past solely through the maternal lineage. This requires an extensive understanding of what may interfere with the tracking procedure, any novel information that can be discerned, and what actions can be taken once results are in. 

When performing a DNA analysis genetic test to trace ancestries and other possible components with a sample that contains mitochondrial DNA, it allows for a one-way ticket to the past. Usually, there are three main types of DNA that can be used to test for tracing history: the chromosomal DNA, used to trace through both the maternal and paternal lines; mitochondrial DNA, used to trace through the maternal line; and nuclear DNA, which can be used on behalf of both parental lines and trace through the entire lineage, even as it diverges into paternal and maternal lineages. Often, in the formation of the embryo to produce offspring through the cohesion of the male sperm and the female egg, although both contain chromosomal DNA, both the sperm and the egg will be able to pass it on, hence chromosomal DNA is traceable through both lines. However, the female egg passes on its mitochondrial DNA, which the male sperm does not give, making mitochondrial DNA something that can be traced only through the maternal line. Although both types of DNA are okay to use, both have their limitations of being able to trace only half of the offspring’s lineage. Yet, when comparing the two types of DNA, the mitochondrial DNA that links the mother’s ancestral genes to their offspring has a stronger link than how the chromosomal DNA links both parents to their offspring. 

Whatever results gained from analyzing unique strands of DNA, particularly narrowing it down to the genes that’s typically passed down from mother, father, or both to the offspring. These genes hold the key to revealing the ethnic backgrounds of the current offspring, yet when mitochondrial DNA is being used to trace ethnicity, it will only track the maternal ethnic background with no regard for the paternal ethnic background. This happens differently with chromosomal DNA, where both maternal and paternal ethnic backgrounds can be analyzed. From decoding these genes and comparing them to congruent DNA strands, it can tell much more than just the ethnicity of a person; it can also reveal health statuses and risks that tested person may be at. For example, some people may have a higher risk of diabetes, since their ancestral genes have shown to have a more heightened risk of developing diabetes than those who are at a normal risk. This is also determined by the genes and whether it’s gained from chromosomal DNA from the male sperm and female egg or the mitochondrial DNA from the sole female egg, yet there is also the issue of gender; sometimes, when analyzing both paternal and maternal genes, it’s often normal to find that females in the family lineage are at higher risk for developing cancer while men aren’t, as well as any other cases in which the genes code to be gender-specific, although exceptions do occur from time to time. 

Analyzing mitochondrial DNA takes a bit of geographical knowledge, especially. All humans were derived from the African continent, where the first evidence of true Homo sapiens appeared before migrating to other parts of the world, where, for hundreds of thousands of years, the global human population would stay relatively under one million. Tracing back to a common ancestor can be studied, analyzing both genotypical and phenotypical characteristics through gene expression while analyzing for mutations, especially those of a more recent origin, as it proves that the generations before the originated mutation will likely have lived in different conditions that did not provoke a mutation to occur, hence allowing the lens of natural selection. Although there are numerable ways in which mDNA can be utilized to account for similarities in each individual, its restriction to the maternal line does limit the information that can be gleaned. 

Mitochondrial DNA, when implemented correctly in DNA testing for any type of results, has its own faults and significances, as well as understanding what it tests for, such as ethnicity, risks of disorders and diseases, and other factors, then finally diving deeply into what value the novel information found may hold and how to use it. Even with the limitation of mitochondrial DNA being traced only through the maternal line, it can still provide a lot of information, as the maternal genes contribute to half of their offspring’s genes, and when necessary, prepare for concerns such as high risks of diseases or other genetic-linked complications.