Since its discovery 20 years ago, the use of DNA for human
identity and relationship testing has emerged as a powerful tool
in both civil and criminal justice systems. DNA testing can
reveal whether two or more individuals are related as well as
determining the nature of their relationship. Today, it is
possible to identify people by a single hair, as well as obtain
information about their gender and ethnic background, and,
within the next couple of years, identify their age.
Before the advent of DNA testing, human identity testing was
largely carried out through blood typing. DNA analysis has now
superseded blood testing and is the most accurate method
currently available for human identification.
The possibility that DNA could be used for human identity and
relationship testing had been discussed from the time DNA was
first revealed as the molecule which makes people unique. Yet,
it was not until the discovery of DNA fingerprinting by Prof.
Alec Jeffreys (now Sir Alec) of Leicester University in 1984
when the first practical testing system became available. As
with conventional fingerprinting, where various loops and whorls
are compared between two fingerprints, DNA testing relies on
comparing certain DNA features called DNA markers between two
individuals. If DNA patterns between the samples are identical,
then they are likely to come from the same person. If the
profiles are not identical but big similarities are observed,
then the samples most probably come from related individuals.
The degree of the similarity between DNA profiles is a representation of the degree of
relatedness between people.
Currently, DNA testing is routinely used for both criminal and
non-criminal applications. However there is a major difference
between DNA testing for civil and for criminal cases. For civil
cases, DNA testing is predominantly used to determine
relationship between individuals while for criminal cases a
crime scene stain has to be matched to the suspect.
In non-criminal legal practice, DNA testing is used primarily
for immigration and child support cases. In 2004, more than
7,000 DNA tests were conducted for these purposes in the UK.
Where no reliable documentary evidence is available, DNA testing
can assist in determining varying degrees of relatedness between
individuals concerned, as well as individual?s ethnic
background.
The first time DNA testing was used for identity purposes was in
the landmark immigration case Sarbah vs. Home Office (1985). In
this case, DNA testing was used to prove the mother-son
relationship between Christiana Sarbah and her son Andrew. Now,
the Home Office accepts DNA testing as a virtually
unquestionable proof of relatedness. The results will normally
(although not invariably) provide conclusive evidence as to
whether individuals in question are related as alleged.
UK Child Support Agency extensively uses DNA testing for
establishing who the biological parent of the child is for
purposes of providing child maintenance and support. Child
support is one the main areas of non-criminal DNA testing.
Child adoption is another area where DNA testing is widely
applied. Currently, UK adoption agencies adopt children into
families which match their ethnic background. Sometimes, it is
difficult to determine the ethical background of the child and
here DNA testing can help. People of different races and ethnic
groups have common facial and other features which are typical
for this particular race or group. The same is also true for
their genetic characteristics. Various racial and ethnic groups
have genetic markers specific to these groups. When analysing
these markers, it is possible to tell the proportion of
individual?s ancestors who came from specific ethnic groups. It
is, however, impossible to pinpoint at what stage the particular
ancestors contributed their DNA and also their number. For
example, the results of ethnicity DNA testing can show
that an individual has 20% of markers specific to northern
Europe, 50% to the Middle East, 10% to the Mediterranean and 20%
to sub-Saharan Africa. Using this information the family with
the closest ethnicity to the child can be chosen.
About the author:
Avi was awarded the prestigious Shell Live Wire Entrepreneur of
the Year award in 2004. Avi strives to increase public awareness
as to the benefits of DNA testing and the
continuing impact that technological advances will have on all
our lives.
|
