DNA Profiling in Parental Testing: Methods, Social Issues, and History

DNA profiling helps determine a unique DNA profile for an individual by analysing DNA from body tissue. Polymorphic regions contain different sequences, and each person inherits a combination of polymorphisms from their parents. DNA profiles are used in crime scenes, paternity disputes, and disaster victim identification. The history of DNA testing dates back to the 1920s, and methods have evolved to include short tandem repeat polymorphisms. Social issues arise when DNA profiling is used to determine parentage, and opposing opinions exist on the matter.

DNA profiling also known as DNA fingerprinting is a process that
helps determine a DNA profile or a fingerprint that is unique to
an individual by extracting and analysing DNA from the body
tissue/s of a person. Although the DNA profile for a person is
unique, it contains portions that are identical to other people's
DNA. But certain specific DNA sequences are variable. These
regions that contain different sequences are called the
polymorphic regions. And the differences in the regions that are
variable between individuals are known as polymorphisms.
Each person inherits a combination of polymorphisms from
his/her parents. An analysis of DNA polymorphisms yields a
person's DNA profile or finger print. DNA profiles find
application when derived from tissue samples at the scene of a
crime or when settling paternity disputes. Relationships
between family members can be confirmed by matching their
DNA profiles. Identification of victims during a disaster, such as
a plane crash, a burnt building or other natural disasters can be
made with the help of DNA profiles.
Introduction
https://www.sciencelearn.org.nz/resources/1980-dna-profiling
http://www.sciencemuseum.org.uk/whoami/findoutmore/yourgenes/
whydoscientistsstudygenes/whatisdnaprofiling
History of DNA Testing
https://dnacenter.com/history-dna-testing/
http://www2.le.ac.uk/departments/emfpu/to-be-deleted/explained/profiling-
history
Methods used by Scientists
https://www.sciencelearn.org.nz/resources/1980-dna-profiling
http://www.yourarticlelibrary.com/dna/dna-fingerprinting-principles-and-
techniques-of-dna-fingerprinting/12211/
Social Issue
Sharma, A. (2007). DNA profiling: Social, legal, or biological parentage. Indian
Journal of Human Genetics, 13(3), 88–92. .
Use of any method for DNA profiling could bring social
issues connected with the child’s parentage into
conflict. Several times, there be cases of genetic
chimeras, where the existing technology cannot
provide answers about the genetic parentage of the
child.
Opposing opinion one
Several parents make use of the assisted reproductive
technology to beget a child. If the father’s sperm
cannot be used, the hospital providing ART may use
the sperm of a donor and not disclose the fact to the
parents, as in the case of Dr Cecil Jacobson, who was
nicknamed ‘babymaker’. If parents of such a child try
using this technology in future they might be in for a
rude shock, on discovering that the social father is not
actually the genetic parent of the child.
Opposing opinion two
There may be cases where the mother has hidden the
identity of the genetic father to avoid embarrassment.
In such cases the resolution of paternity dispute may
be done using DNA profiling but it may cause social
embarrassment to the family or it may complicate the
matters of legal inheritance and the child may lose the
right to inherit the social father’s property. This may
help the father’s biological children to inherit the
property and not have to share it with a half sibling
depending on the inheritance laws of the country they
live in.
.
Introduction
History of DNA Testing
Social IssueMethods used by Scientists
References
.
In the 1920s, the ABO system of blood typing based on blood
antigens was known. It could be used to determine paternity in
some cases but in cases where the mother had type AB and the
child had an A blood group, the father could have any of the 4
blood groups.
By the 1930s, the serological testing was developed to aid blood
typing with the help of antigens, such as Rh, Kell and Duffy, but
only 40% of the cases could be resolved using this method.
In the 1970s HLA testing was developed, and the typing based
tissue antigens with blood typing could be used to answer
questions on biological relationships by upto 80%.
By 1980s, genetic testing to confirm paternity was used, the
method used was RFLP-Restriction fragment length
polymorphism. The procedure makes use of restriction enzymes to
cleave DNA and determine the variable number tandem repeats. A
child inherits 50% VNTRs from the mother and 50% from the
father. 99.9% exclusion is possible using this method, the only
drawback is the long turnaround time. Polymerase chain reaction
and single nucleotide polymorphisms were also used to confirm
paternity.
Short tandem repeat polymorphisms is one of the current
techniques used to solve paternity disputes. The method involves
comparison of the number of short tandem repeats at ten
different genetic loci on the genome.
What is a DNA profile?
A DNA profile using the single tandem repeat method can be done by
examination of STRs at genetic loci in 10 different locations/loci on
the genome, chosen such that they lie on different chromosomes. It is
possible to determine a person's gender from a DNA profile and
whether a sample of DNA that has been tested belongs to an
individual. It is almost like a DNA fingerprint and is therefore unique
to each person.
How are STRs employed to create a DNA profile
1. Collection of a sample of DNA
Since almost all cells of the body contain DNA, a sample of DNA could
be collected in the form of white blood cells from a whole blood
sample, semen, roots of hair, body tissue, even the saliva or
perspiration contain epithelial cells that could be used to collect DNA.
When at a crime scene, forensic experts or the police may collect
samples. A person's cheek cells can be collected from the mouth
using a swab to extract DNA.
2. Extraction and amplification of the DNA
DNA is inside the nucleus of the cell and the cells have to be
subjected to a series of chemicals that can break open the nuclear
envelope and DNA can be isolated and separated from other contents
of the cell. At times a forensic sample of DNA may be very small so
the extracted amount of DNA is not sufficient to carry out the
procedure of DNA profiling. At such times, DNA can be amplified
using a polymerase chain reaction (PCR). While amplification, primers
are used such that the regions containing the STRs are amplified a
fluorescent tag is also attached to the STRs.
3.Determination of the size of the STRs
A genetic analyser is used to determine the size of the STRs at each of
the genetic loci. The copied DNA is separated using gel
electrophoresis. The analyser then detects the fluorescent dye that
each of the STR DNA is tagged with. This equipment is the same as
the equipment used for DNA sequencing.
4. Do the STRs of DNA from two or three sources match?
The size of the STR depends on the number of times a nucleotide
sequence is repeated along its length. The number of repeats of the
sequence help in determining the source or person whose DNA it
could be. If DNA profiles for two samples are found to be identical,
the source is one individual, because each person's DNA profile is
unique.
DNA profiling in parental testing

DNA profiling also known as DNA fingerprinting is a process that
helps determine a DNA profile or a fingerprint that is unique to
an individual by extracting and analysing DNA from the body
tissue/s of a person. Although the DNA profile for a person is
unique, it contains portions that are identical to other people's
DNA. But certain specific DNA sequences are variable. These
regions that contain different sequences are called the
polymorphic regions. And the differences in the regions that are
variable between individuals are known as polymorphisms.
Each person inherits a combination of polymorphisms from
his/her parents. An analysis of DNA polymorphisms yields a
person's DNA profile or finger print. DNA profiles find
application when derived from tissue samples at the scene of a
crime or when settling paternity disputes. Relationships
between family members can be confirmed by matching their
DNA profiles. Identification of victims during a disaster, such as
a plane crash, a burnt building or other natural disasters can be
made with the help of DNA profiles.
Introduction
https://www.sciencelearn.org.nz/resources/1980-dna-profiling
http://www.sciencemuseum.org.uk/whoami/findoutmore/yourgenes/
whydoscientistsstudygenes/whatisdnaprofiling
History of DNA Testing
https://dnacenter.com/history-dna-testing/
http://www2.le.ac.uk/departments/emfpu/to-be-deleted/explained/profiling-
history
Methods used by Scientists
https://www.sciencelearn.org.nz/resources/1980-dna-profiling
http://www.yourarticlelibrary.com/dna/dna-fingerprinting-principles-and-
techniques-of-dna-fingerprinting/12211/
Social Issue
Sharma, A. (2007). DNA profiling: Social, legal, or biological parentage. Indian
Journal of Human Genetics, 13(3), 88–92. .
Use of any method for DNA profiling could bring social issues
connected with the child’s parentage into conflict. Several
times, there be cases of genetic chimeras, where the existing
technology cannot provide answers about the genetic
parentage of the child.
Opposing opinion one
Several parents make use of the assisted reproductive
technology to beget a child. If the father’s sperm cannot be
used, the hospital providing ART may use the sperm of a
donor and not disclose the fact to the parents, as in the case
of Dr Cecil Jacobson, who was nicknamed ‘babymaker’. If
parents of such a child try using this technology in future
they might be in for a rude shock, on discovering that the
social father is not actually the genetic parent of the child.
Opposing opinion two
There may be cases where the mother has hidden the
identity of the genetic father to avoid embarrassment. In
such cases the resolution of paternity dispute may be done
using DNA profiling but it may cause social embarrassment
to the family or it may complicate the matters of legal
inheritance and the child may lose the right to inherit the
social father’s property. This may help the father’s biological
children to inherit the property and not have to share it with
a half sibling depending on the inheritance laws of the
country they live in.
.
Introduction
History of DNA Testing
Social IssueMethods used by Scientists
References
.
In the 1920s, the ABO system of blood typing based on blood
antigens was known. It could be used to determine paternity in
some cases but in cases where the mother had type AB and the
child had an A blood group, the father could have any of the 4
blood groups.
By the 1930s, the serological testing was developed to aid blood
typing with the help of antigens, such as Rh, Kell and Duffy, but
only 40% of the cases could be resolved using this method.
In the 1970s HLA testing was developed, and the typing based
tissue antigens with blood typing could be used to answer
questions on biological relationships by upto 80%.
By 1980s, genetic testing to confirm paternity was used, the
method used was RFLP-Restriction fragment length
polymorphism. The procedure makes use of restriction enzymes to
cleave DNA and determine the variable number tandem repeats. A
child inherits 50% VNTRs from the mother and 50% from the
father. 99.9% exclusion is possible using this method, the only
drawback is the long turnaround time. Polymerase chain reaction
and single nucleotide polymorphisms were also used to confirm
paternity.
Short tandem repeat polymorphisms is one of the current
techniques used to solve paternity disputes. The method involves
comparison of the number of short tandem repeats at ten
different genetic loci on the genome.
What is a DNA profile?
A DNA profile using the single tandem repeat method can be done by
examination of STRs at genetic loci in 10 different locations/loci on
the genome, chosen such that they lie on different chromosomes. It is
possible to determine a person's gender from a DNA profile and
whether a sample of DNA that has been tested belongs to an
individual. It is almost like a DNA fingerprint and is therefore unique
to each person.
How are STRs employed to create a DNA profile
1. Collection of a sample of DNA
Since almost all cells of the body contain DNA, a sample of DNA could
be collected in the form of white blood cells from a whole blood
sample, semen, roots of hair, body tissue, even the saliva or
perspiration contain epithelial cells that could be used to collect DNA.
When at a crime scene, forensic experts or the police may collect
samples. A person's cheek cells can be collected from the mouth
using a swab to extract DNA.
2. Extraction and amplification of the DNA
DNA is inside the nucleus of the cell and the cells have to be
subjected to a series of chemicals that can break open the nuclear
envelope and DNA can be isolated and separated from other contents
of the cell. At times a forensic sample of DNA may be very small so
the extracted amount of DNA is not sufficient to carry out the
procedure of DNA profiling. At such times, DNA can be amplified
using a polymerase chain reaction (PCR). While amplification, primers
are used such that the regions containing the STRs are amplified a
fluorescent tag is also attached to the STRs.
3.Determination of the size of the STRs
A genetic analyser is used to determine the size of the STRs at each of
the genetic loci. The copied DNA is separated using gel
electrophoresis. The analyser then detects the fluorescent dye that
each of the STR DNA is tagged with. This equipment is the same as
the equipment used for DNA sequencing.
4. Do the STRs of DNA from two or three sources match?
The size of the STR depends on the number of times a nucleotide
sequence is repeated along its length. The number of repeats of the
sequence help in determining the source or person whose DNA it
could be. If DNA profiles for two samples are found to be identical,
the source is one individual, because each person's DNA profile is
unique.
DNA profiling in parental testing
Sir Alec John Jeffrys:
The man who invented the technique of DNA profiling