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.