DNALabs can test for biological relationships for the following:

Sibship

DNA testing methods can provide information about relationships within a family. An analysis of whether two people (regardless of sex) are full or half siblings can be performed. However, unlike paternity testing, which provides very conclusive results, sibship analyses are not as conclusive. If two people are full siblings, mathematically we expect them to share 50% of the genetic markers we test. If two people are half siblings, then 25% of their genes will be common. This principle then allows us to determine statistically the chance that they would share the DNA if they are siblings, compared to if they are unrelated (ie. if they matched by chance - population frequency). It is not possible to determine with 100% certainty whether or not two people are siblings.

Female Relationship Testing - (X Chromosome Testing)

Females inherit two X chromosomes, one from their mother and one from their father. Males have a single X chromosome and a single Y chromosome. Mothers will randomly assign one of their two X chromosomes to each of their children. All the daughters of a man will share his only X chromosome. Extracted DNA samples are analysed at variable or polymorphic sites and compared to distinguish the origin of each X chromosome. Where two females share a mother and are trying to determine if they share a father, the mothers DNA sample is also required for testing.

Male Relationship Testing - (Y Chromosome Testing)

In addition to the maternally inherited X chromosome, males have a single Y chromosome passed on from biological father to each son. The inheritance of the Y chromosome is strictly from male to male and will be shared by all male members of a common male predecessor, provided the male line is in place.

This testing can be used to establish if two men come from a common paternal line, which can include relationships such as siblings, uncle/nephew, cousins and many other possibilities. It should be noted that while this testing links back to a common line, it does not distinguish brothers from paternal cousins or sons from grandsons etc.

Extracted DNA samples are analysed at polymorphic sites and compared to distinguish whether the individuals share a paternal line. For this to be true they need to match at each locus.

Other combinations

Other family relationship and identification issues can be resolved using DNA identification technology. The reports issued for our relationship enquiries can support cases for deceased estates, Immigration applications and other legal matters where paternity or maternity testing may not be available.

Who needs to be tested?

Each relationship enquiry is different and the testing may be determined by who is available to test. Our team will assist with your enquiry to determine the best test available to establish if a biological relationship exists.

Relationship testing applciation form can be downloaded here or please contact us on 1300 663 244 or email info@dnalabs.com.au to discuss your enquiry.