1.877.777.4004
info@paternitycanada.com
F-2020 Corydon Ave.
Winnipeg, MB, Canada
R3P 0N2
Understanding My DNA Report
Your DNA report presents the genetic profile for each tested party and two (2) important values used to determine if the tested
parties are related. These values are the Combined Relationship Index and the Probability of Relationship.
Definition of Terms
Locus:
A specific region of the DNA molecule (ex. D3S1358)
Allele:
A genetic variation found at a specific locus. In the DNA report, alleles are represented by numbers (ex. 16-17). For
each locus, one allele comes from the mother and one allele comes from the father.
Index:
This value represents the strength of the genetic evidence based on the frequency of each allele in the population.
It indicates whether the genetic evidence is more in agreement with the tested parties being related or more in
agreement with the tested parties not being related.
Probability:
A way to express the strength of a biological relationship. It is based on the genetic evidence (combined index) and
non-genetic evidence (prior probability). Since the laboratory does not possess information on non-genetic
evidence, the prior probability is fixed at 50%.
DNA Analysis
Example of a POSITIVE paternity test
Locus
D3S1358
FGA
D21S11
D13S317
1.
2.
3.
4.
5.
6.
Mother
16 – 17
22 – 27
34 – 35
12 – 13
Child
15 – 16
22 – 23
27 – 35
10 – 12
Alleged Father
15 – 17
21 – 23
27 – 28
10 – 14
Combined Paternity Index
Probability of Paternity
Paternity Index
1.79
2.64
8.47
21.65
866
99.88%
Identify the allele that the mother gave the child (red) at each locus
Check if the tested alleged father has the child’s other allele (blue)
If there is a match, the paternity index is calculated for each locus
The index values are then multiplied to give the combined paternity index
The combined paternity index is converted to the probability of paternity
A probability of paternity >= 99.8% confirms the paternity of the tested father
Example of a Negative paternity test
Locus
Mother
Child
Alleged Father
Paternity Index
D3S1358
16 – 17
15 – 16
12 – 19
Exclusion
FGA
22 – 27
22 – 23
19 – 23
D21S11
34 – 35
27 – 35
27 – 28
Exclusion
1. Identify the allele that the mother gave the child (red) at each locus
2. Check if the tested alleged father has the child’s other allele (blue)
3. If there is no match for at least 2 loci, the tested alleged father cannot be the father of the child since he does not possess
the alleles that the child received from his/her biological father
4. The probability of paternity is 0%
Please contact us if you require more information. We would be happy to assist you in answering your questions.
Ph. 1.877.777.4004 •
Em. info@paternitycanada.com •
Addr. F-2020 Corydon Ave. Winnipeg, MB, Canada, R3P 0N2