Understanding Genetics - For Beginners
Every one of us is unique beyond our surface individualities. We may consider our personalities, looks, and skills as the factors that make us distinct - but, aside from our experiences and circumstances, it is in fact our genetics that really determines how unique we actually are.
Our genes are the driving factor behind our appearances, they explain how our bodies function, and they even exert influence on our personalities - they are the operating instructions inside each and every one of our cells.
However, sometimes the process of analysing DNA may seem like a foreign language. One which you may be too tentative to venture into. However, the undertaking can be understood by breaking it down into the sum of its parts - the type of DNA that is analysed, what it can tell you, and the steps taken during a DNA analysis.
What is Autosomal DNA?
Within the field of genetic genealogy, autosomal DNA refers to the DNA that is inherited from the autosomal chromosomes - that is, the 22 numbered chromosomes that humans have rather than the one chromosome associated with sex (the X and Y chromosome). The autosomal chromosomes are numbered in accordance to their size, thus, the lower numbers have a larger amount of genes held within the chromosome in comparison to the higher numbers.
Autosomal DNA tests are widely used to provide links/matches with potential family members, and also for health reports which provide risk factors for certain diseases. However, more detailed information is required to determine the specifics of a genetic relationship - such as more DNA from different family members. For genetic relationships that extend further than the fifth cousin, such as connections to ancient civilisations, then triangulation, Y-DNA, and mtDNA are usually used.
What is a Y-DNA test?
A Y-DNA test involves testing the male patrilineal line of ancestry - the Y chromosome. This male chromosome is passed down from father, to son, to grandson, effectively unchanged. Thus, this form of DNA is passed down to the males in the family, but not daughters. Sometimes, a rare mutation to the chromosome can occur, but this often allows scientists to estimate the time when the mutation occurred and more accurately determine a shared ancestor, or a specific population.
It is typically relatively easy for a male to follow his patrilineal ancestry, as they can follow their surname back through their family. However, if their background is atypical, then they may choose to go down the route of Y-DNA testing. If a woman wishes to do a Y-DNA test to determine their paternal DNA ancestry, they would have to request a related male family member from their paternal line to take a test for them.
What is a mtDNA test?
In opposition to a Y-DNA test which tests the male line of ancestry, a mtDNA test - or mitochondrial DNA test - tracks an individual’s matrilineal line using the information held within the mitochondria of their cells. This type of DNA is passed through the mother-line to all of her children, regardless of whether they are male or female. What ‘s more, this DNA is virtually unchanged between generations. For these reasons, an mtDNA test can be taken by either men or women that are hoping to determine their ancestry.
What is Triangulation?
The process of triangulation is used in many fields, including psychology, map-making, etc., but it is used within genetics to determine an ancestral haplotype (the set of DNA variations that are typically inherited together). This means that a shared ancestor can be found through comparing an individual's known genetic relationships.
We hope that you now feel that the concept of DNA analysis is less confusing or daunting in light of all the information that we have provided in this article. After all, you’re only a couple of steps away from finding out more about yourself from how your genetics links to the past!
