How a Paternity Test is Determined With Genetic Markers

If you are wondering whether you are the father of a child, you may want to consider taking a DNA test. A DNA test can tell you whether you are the biological father by analyzing the genetic markers that are found in your DNA and the child’s DNA. Once your paternity test has been analyzed and processed, you will have the answers you need. By answering these few questions about markers and DNA, you can have a better understanding of how your paternity test will be used to determine whether you are the father or not.

How is DNA Inherited?


As most people know, DNA comes from both of the biological parents of a child. Also known as deoxyribonucleic acid, DNA is found in every cell of the body.  There are four different molecules from which it is composed:


  • Adenine (A)
  • Thymine (T)
  • Cytosine (C)
  • Guanine (G)


Each of these molecules is laid out in specific patterns and sequences to give instructions to our body for functions that we use every day. DNA can determine what our physical characteristics will be such as a big or small nose, hair color, eye color, height, and any health issues we may have. During the conception process, half of the mother’s DNA and half of the father’s DNA come together through the egg cell and sperm cell, respectively. These two halves form a zygote, or fertilized egg, and contain a complete DNA set which is a combination from both of the parents. As the fetus grows, every new cell contains this same DNA. This is what allows scientists to determine parentage because you have pieces of DNA from your father and your mother that are unique to you as an individual.


What Are Genetic Markers?


According to, in order to identify individuals, a DNA sequence or gene with a specific location on a chromosome, also known as a genetic marker, is used. This genetic marker can be a short sequence or a long one, and may also be a variation. Markers can be divided into biochemical markers and molecular markers. The first class, biochemical, is used to look at variation or changes at the gene product level. These changes could include proteins and amino acids. The second class, molecular, is used to find variation at the DNA level. These may include:


  • Deletion
  • Inversion
  • Insertion
  • Duplication


These markers can display two means of inheritance: co-dominant or dominant/recessive. Usually co-dominant markers give a lot more information than its dominant counterpart.


How Are Markers Used?


Markers can be used in a variety of ways such as determining the relationship between a genetic cause and an inherited disease or genealogical DNA testing. With inherited diseases, the inheritance pattern can be determined by the DNA because parts of DNA that are found near each other on a chromosome are usually inherited together as well. Because of this, even if the gene does not have a specific known location, the information can still be determined. In order to determine the relationship between two individuals with DNA testing, uniparental markers can be utilized. If you want to know if you are the father, the Y chromosomal DNA is studied to access the information.


How is DNA Used in a Paternity Test?


Certain locations in the DNA sequence can display inheritance patterns that are predictable and perfect for determining biological relationships. These specific sequences of DNA are called markers and can be used for individuals as identifying marks. Short Tandem Repeats (STRs) are the markers that are used in paternity tests. These are short pieces of your DNA that are found in different repeat patterns. Because each individual has two copies of the markers from their father and their mother, the markers could vary in length and sequence at each DNA location. This combination makes up each individual’s genetic profile. When analyzing a paternity test, most scientists will examine at least 16 markers to create this profile for each person that is being tested. Once this is done, the genetic profiles are compared to determine whether there is a match. If the child has pieces that match the father, he or she may be the biological offspring of the parent.

To find out the biological parentage of a child, it is necessary to take a paternity test. With the use of DNA and markers, it can be determined whether the child has the same pieces of DNA from the father. With the answers to these few questions, you can understand how this process works and hopefully get the results you are looking for.

About Suzi

Suzi is an American ex-pat living in British Columbia. She's a cloth diaper addict, wife, mom of three, and President of the Prince George chapter of Cloth for a Cause.

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