The Pringle DNA Project Update - March 2011

Now that we have 20 male participants, the results of the tests have been analysed in the pdf file. Personal details have been removed from the analysis leaving the customer codes and sample codes for reference. An excellent explanation of Y-DNA testing can be found on the Blair Family DNA Project website which has over 500 participants. I give below my own very simplified explanation:

The human genome (or molecule), which is like a twisted ladder with rungs, comprises 46 chromosomes of which 23 are contributed by the mother and 23 by the father. Each side of the ladder, or backbone of the DNA molecule, is made of sugar and phosphate and is held together by rungs called base pairs which form a weak bond, combining in a set manner: adenine (A) pairs with thymine (T), while cytosine (C) pairs with guanine (G). Base pairs are the foundation of Y-DNA chromosome testing, or indeed any DNA testing.

This ladder is the DNA sequence specifying the exact genetic instructions required to create a human with his / her own unique traits. It is, as it were, the “computer” code to make a human being. The Y chromosome is a section of the ladder which is exclusive to males. Markers are rungs of the ladder selected at known and defined points to test the pairs which make up those rungs. In the case of our tests these markers are selected within the Y chromosome. There is a considerable amount of redundancy i.e. safety from error built into the rungs so that mistakes and mutations do not occur easily. This is controlled genetically by instructions being repeated many times e.g. gctagctagctagcta etc. It is these repeats that are measured / counted in the tests. This genetic code is passed on from father to son and the number of these repeats rarely change over many generations. For this reason Y-DNA tests are very reliable evidence of male relationships (or lack thereof) within a family group.

Analysis of Results (.pdf file)