Family Studies DNA Test
The technology used for DNA testing can often be applied to special applications called Family Studies. In these situations, rather than answering the question “Is this man the father of the child?”, different or more involved questions can be assessed, testing the likelihood of other biological family relationships. The same genetic markers that are used in standard Paternity Test are used to determine paternity when the alleged father is deceased or unavailable for testing (using grandparentage DNA Testing), to assess whether other people are biologically related such as possible brothers (siblingship, or sibship studies), and even whether twins are genetically identical (twin studies). In Estate settlements, establishing or proving such family relationships can provide important information.
In cases where there is a question about a biological relationship between a child and a possible grandparent, the Identity DNA Test should include samples from the child, the mother and one or both parents of the alleged father. Such a DNA Test is used when the alleged father is deceased or unavailable for testing. Similarly, a family study involving aunts, uncles or other related parties can often be used to conclusively establish a relationship – for either legal or personal purposes.
Siblingship or “Sibship” Testing
A DNA Identity Test designed to determine whether two people have biological parents in common is known as a “siblingship study” or “siblingship test.” Individuals are full siblings when they have the same biological parents, or half siblings when they share one biological parent, either a mother or a father. To perform this DNA Test, two or more individuals who are interested in establishing whether or not they have parents in common provide DNA samples. Although it is optional, we strongly recommend including a sample from the parent in the test, when it can be provided.
Fraternal (dizygotic) twins are formed from two eggs, fertilized separately, which can result in two siblings of the same or opposite sexes. The hair and eye color, as well as many of the other characteristics of fraternal twins, can vary widely — and fraternal twins can actually be half-siblings, with different fathers. The fact that such genetic differences exist can be confirmed by DNA testing. In contrast, identical (monozygotic) twins occur when a single fertilized egg splits after conception into two identical halves, each of which develops separately. Each identical twin will have exactly the same DNA, a fact which can be established through testing. Of course, identical twins are of the same sex and have the same eye and hair color, as well as blood type. Only one of every three sets of twins are identical.