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DNA Analyisis
Parentage, Paternal, Siblingship, Immigration


In a case where there is an immediate need to determine parentage, prenatal DNA parentage analysis is also available. Sample collection method will vary depending on the stage of pregnancy. In general, pregnancy of time length of 10-13 weeks and 14-24 weeks, procedures will be done by Chorionic Villi Sampling and Amniocentesis, respectively. To arrange for prenatal specimen collection, please contact your OB/GYN physician. We will provide all necessary forms and specimen collection kits.

3. Reporting of Results

Results will be available within 9-14 working days. This will be reported as 0 % or > 99 % for non-matching child and alleged father, and matching child and /alleged father, respectively.

Generation and Interpretation of DNA Analysis Results

We realized the technical complexity of doing DNA analysis. It is our pleasure to discuss with great simplicity of how the results of DNA analysis is reached and reported.

The basis of DNA Paternity analysis assumes a 50 % probability that the alleged father is the father of the child. As mentioned earlier, paternity is determined by searching for an exact matching allele size (gene) of the parent with the allele size of the child.

To interpret the DNA analysis result, there are a few important simplified technical terms to consider.

Allele - a component that carries the genetic information or traits that are contributed by the mother and father, and occupies a specific position in a chromosome. Allele comes in pair which vary in size from one individual to another.
Allele size - a factor that is use in determining whether or not a match exist. This is indicated by measuring the size of the allele in kilobase pairs (kbp). For example, one half of the allele pair from the mother's allele was measured to be 2.75 kbp and the other half was measured at 1.25 kbp. Since an allele is in pair form, one half of allele size of each pair will match the father and the other half of the allele size will match the mother. See Figure 1.
Chromosome - a structure that contains DNA which transmits information. Human beings contains a total of 46 chromosomes contributed by one half from the father and mother.
Gene - the basis of heredity, self-generating and located on an exact position (locus) on a particular chromosome.

Locus - The location of the gene in a chromosome

Paternity Index (PI) - A devise of generating odds (Probability of Paternity - see below) for the alleged father with a matching allele indicating that he is the true father of the child of interest. The PI refers to the specific DNA probe use in DNA locus identification. Additionally, PI vary in odds depending on type of probe use. For example, DNA Probe DC1 with PI 200 and DNA Probe DC2 with PI 30 denotes one out of every 200 and one out of 30, respectively males of same race will have similar allele size.

Calculating Probability of Paternity (PrP)

Formula; PrP (%) = (1/CPI -1) x 100
Example 1
DNA Probes            PI Value
A1 (15)                         A2 (25 )

A3 (22.5)                     A4 (60.3 )

Step 1. Multiply the PI Values, CPI;  CPI = 15 x 25 x 22.5 x 60.3 = 108,781
Step 2. Plug the CPI value to the equation of
                              PrP (%) = (1/CPI -1) x 100

                              Probability of Paternity (PrP) = (1/508,781) -100 = 99.999 %

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Copyright 2004 [Toxicology Associates, Inc.]. All rights reserved.
Revised: January 11, 2013