A Guide to complex DNA Testing
Complex DNA testing can establish whether a biological relationship exists between two or more people.
As such, we use these tests to establish the following:
- Grandparent DNA Testing. To establish the biological grandparents of a child. Also, this test can show paternity in an indirect way.
- Avuncular DNA Testing. This is also known as Aunt DNA Testing or Uncle DNA Testing.
- Also. we can use a number of other combinations to test the above.
The Complex DNA Test Explained
We produce a DNA test profile for each test participant. The test analyses different genetic locations on the DNA strand. We identify each allele (alternating form of DNA) at each location using a number. Then, we compare the DNA profiles of each test participant. In this case, the premise is that related individuals should have more DNA in common than unrelated individuals.
Inconclusive Results and Test Limitations
The statistical analysis uses the following factors:
- The number of allelic matches within the DNA profiles.
- The likelihood of finding the same allele at the same DNA location. We compare this against a random, unrelated individual with the same ethnicity.
These calculations determine the most likely relationship between the individuals tested.
How are Complex DNA Test results interpreted?
We use the values from the calculations to generate a percentage probability value. Then, based on the circumstances provided, we will generate a set of hypotheses. The calculation compares each hypothesis to determine which scenario is more likely.
The percentage probability will usually fall into one of the three following categories:
0-10%
When we get a percentage probability in this range, the evidence suggests that this relationship DOES NOT exist. Or, it could be that the hypothesis suggested is incorrect.
90 – 100%
When we get a percentage probability in this range, the evidence suggests that this relationship DOES exist. In other words that the hypothesis suggested is correct.
10 – 90%
If we get a percentage probability within this range, it can yield an INCONCLUSIVE result. This means that the laboratory does not have enough evidence to provide a result. Thus, we cannot determine which relationship/hypothesis is more likely.
An INCONCLUSIVE result is rare. But we cannot issue conclusive results unless they provide very strong evidence that a relationship does or does not exist.
Causes of inconclusive results include:
- The alleles shared between potential relatives are common within the relevant general population. In other words, there is insufficient genetic evidence to confirm which relationship exists.
- There is a low level of allelic (number) matches in the DNA profile. This is due to the chance nature of inheriting alleles within families (as explained above).
- Mutation causing mismatches at further locations within the DNA profile.
If we provide an INCONCLUSIVE result, there may be a need for further analysis. In turn, this could incur extra charges.