About this analysis
Men only have one X chromosome from the biological mother whereas women have two, one from the mother and one from the father. As the father only has one X chromosome, it will always be the same as the one transmitted to his daughter(s).
We study the STRs of the X chromosome of the alleged daughters. We separate the mother’s chromosome (this is why her participation is necessary) so that the one which is left is that of the biological father. Next, we compare the two paternal X chromosomes.
If it coincides, we can be sure that they are sisters with the same biological father, with a reliability in excess of 99.99%. The participants are sisters with the same father.
However, if they do not coincide, it will reveal that the participants are not daughters of the same biological father and therefore, not paternal sisters, with a reliability of 100%.
After the comparison, our team carries out a statistical study based on complex calculations of allelic frequencies. This study enables us to conclude our investigation with values exceeding 99.9% reliability.