DNA Testing What it Cannot Tell You

12 Aug 2017

DNA testing can tell you many things. Nowadays Paternity DNA tests can clearly establish whether an individual is a child’s biological father. Tracking your ancestry can be done by means of an ancestry test and now there is a growing demand for genetic predisposition tests which can tell you the probability of developing certain autoimmune diseases.

Specificity of a DNA Test: A DNA test, such as a paternity DNA test or an X-chromosome test cannot give you any other information besides what the test specifically sets out to do. Thus, an X-chromosome test can tell you whether two alleged siblings share the same father or not, a paternity test can tell you whether an individual is or is not your biological father. Neither of these tests or any other DNA test can give you other information that is not directly related to the scope of the test. An X-chromosome test will not tell you whether you are predisposed to a hereditary cancer or another illness. If you wish to find what hereditary diseases you are likely to get then you will need to do a genetic predisposition test.

Clients often do MtDNA tests to know whether they share the same maternal line. The test answers exactly that question: do you share the same maternal line? It will not tell you whether an individual tested is your mother, your aunt or the exact relationship you may have. It will simply tell you whether you share a common maternal line.

A DNA test will not tell you what the hair colour of your child will be or how old your father or any person being tested may be. This may seem obvious to many of us, but genetic testing is a very recent phenomenon and we can thus understand clients who ask such questions. Moreover, whilst the current generations are educated on what DNA is at school and therefore, have a background, older generations may be still unaware of what DNA testing exactly does.

Here below are some of the things that genetic/DNA testing cannot yet do

An Ancestry DNA Test: Can it Tell me my Family Tree?

The aim of an ancestry DNA test is to locate matches with anthropological regions and find your geogenetic heritage. The analysts will make links between your genetic information and your genetic heritage by means of a database. The test will tell you whether you have African, European or other possible groups of ancestors by telling you which native groups you have strongest links with. Your genetic testing includes a graphical representation of the results and a detailed report.

Whilst an ancestry test can do all of the above and be a good source of information regarding your ancestry, it cannot tell you who your ancestors are and map out family trees for you. Locating specific ancestors and finding their names, those of their children and different branches of the family requires much more research involving genealogists, lengthy searches through birth records and archives and a lot of money.

A Word on Designer Babies: genetic testing means that you could pick the hair colour, eye colour and height of your child and actually draw up a multitude of features you desire your baby to have. However, scientists still do not know which genes are activated for which physical traits. ‘Making’ designer babies involves a more simplistic approach to genetics: if you want a child with blue eyes then you make sure that the DNA used to ‘make’ the child comes from parents who both have blue eyes and whose grandparents have blue eyes too.

This type of testing can tell you many things however it is important to also understand what the DNA test cannot tell you.