DNA Testing: Unravelling Biological Mysteries

neil-patrick-harris-600x450

Can Twins have different fathers?

Actor Neil Patrick Harris and husband David Burtka opted for surrogacy to become parents, for which both their sperms were taken to fertilize the eggs of a donor, and then introduced into the surrogate’s uterus. Interestingly, eggs fertilized by both their DNA, were attached to the uterus, resulting in twins, each of whom have one of their fathers’ DNA (Massarella, 2012). This is a situation where one is already aware of the fact that there are two fathers, due to the fact that the zygotes were created in a laboratory.

Sometimes twins can have different fathers, even when they are conceived through sexual intercourse. Reports of the same have popped up in 2015, when twin girls with different fathers were born in New Jersey (Assefa, 2015). In that case the father of one oexample-of-twins-who-probably-might-be-of-different-fathersf the twins whose DNA was matched, was ordered to pay child support for the child that he had fathered. In March 2016, twins in Vietnam were born of the same phen
omenon. It was discovered after the family suggested that the father should get a paternity test done, since both the children looked very different from one another (Massarella 2012)(Sample, 2016). This phenomenon is termed as heteropaternal superfecundation, and can be determined only by performing DNA tests whether the twins have the same father.

 

Is maternity testing feasible?

DNA testing can be used to determine the mother as well as the father of the test subject. As opposed to fathers, one is usually aware of who the biological mother is, unless they have been adopted. Even so, mitochondrial DNA is often used to determine maternity, and can be useful to secure the identity of victims of violent crimes, where the body has been mutilated beyond recognition and normal DNA is much destroyed. If you remember biology from school, you will know that “the mitochondria is the powerhouse of the cell”, which means that there are usually more number of there organelles in the cell compared to only one nucleus where nuclear DNA is present. Due to the multiple copies of the organelle present, it is easier to obtain mitochondrial DNA from a fairly degraded or damaged cell, since it forms a considerable fraction of every cell’s genetic material. Moreover, mitochondrial DNA is always inherited from the mother and therefore is carried by all progeny but not passed on by human males to their children. Mitochondrial DNA has often been used to trace back family trees to hundreds of years ago, even as far back to our ancestral mother Eve in Africa, and can be useful for determination of identity via genealogy.

31-genes-10-638

 

Alleles are the part of human genetic material – chromosomes – responsible for the dominant and recessive genes that are inherited from the parents. Every human has two alleles located in pair of chromosomes, one from each parent. Alleles can be matched, both in cases of male and female offspring. Minor mutations may occur as the genetics of the child would adapt to the surrounding situations in their environment, to help them survive better. However, these kinds of changes are extremely rare and may occur once, rarely twice, between two generations. Therefore, in spite of 1 mismatch between alleles, we can still establish a biological connection between a child and a potential father confidently.

image

How does a paternity test work?

In determining the paternity of a person, alleles on chromosomes are matched between the potential father and the subject. The Y chromosome is inherited from the father to the son largely unchanged, which means that the same Y is probably transferred across paternal lineage. While it can be used to identify a man using his father’s DNA, it cannot be used for paternity testing, for the inheritance could have occurred from the tested man or any of his male relatives.

Siblings have the same genetic inheritance and may occasionally show a considerable degree of allelic match. This could be a tricky situation if the brother of the tested man is the one who has actually fathered the child. This is why it is important to test all potential subjects, to find the most probable match. Genetic comparison can be difficult if the potential father refuses to cooperate with the procedure, since their biological material cannot be obtained without their permission. This is because it has been enshrined in the Indian Constitution that “no person accused of any offence shall be compelled to be a witness against himself”. The only exception to this rule is when there is a judicial proceeding being carried out against the potential father, and it requires determining their paternity. In such a case, the judge could pass an order to obtain the DNA of the person, with which he would have to comply.

In 2014, the High Court of Delhi ruled that Mr. N. D. Tiwari, a senior congress leader, is the biological father of Mr. Rohit Shekhar, of whose existence Tiwari had no knowledge of. The Court had ordered a DNA sample to be obtained as a result of request from Mr. Shekhar’s lawyer. The test on the sample revealed that the two of them were related. Even after the certified copies of the results were attached with the court file, Mr. Tiwari refused to admit that inference had any truth to it. His claim was that it was tampered with, or that the analysis wasn’t correct. This, coupled with the fact that there were some photographs which proved that Mr. Tiwari knew Mr. Shekhar’s mother, Mrs. Ujjwala Sharma, led the Court to believe that he actually fathered Mr. Shekhar, especially because Mr. Tiwari had previously denied knowing Mrs. Sharma before the photograph was produced.

tiwari_pkg1

Although the case against Mr. Tiwari may have been proved beyond reasonable doubt, one could always anticipate; especially in cases where a connection can be established betweenthe mother and the potential father as well as any of his other directly related male relatives, such as brother, father, son, etc. The contention that the evidence might have been tampered with also may hold some value, if it can be proved. There are strict rules that are to be followed with respect to packaging and forwarding any evidence in a case, this evidence has to be in the custody of someone who is authorized to analyze it, or transfer it, etc. All of this should be recorded, any anomaly would be noticed on a close examination of the records in Court thereby proving tampering, which would make the evidence inadmissible in Court. Since no reasonable explanation has been offered in support of either of the claims of Mr. Tiwari, it cannot create reasonable doubt against Mr. Shekhar’s case.

There can be a lot of confusion with respect to the potential father cases where the close male relatives have a connection of some sort with the child’s mother, which may lead one to believe that they may have been sexually involved.. This idea has been captured in fiction, in Castle, season 2, episode 8, ‘Kill the Messenger’, wheMV5BMjMwMDY0OTQ2N15BMl5BanBnXkFtZTgwMTc2NDM0MjE@._V1__SX1394_SY709_re due to a new murder, the team of detectives had to reopen a decade old murder case. In the past, the victim, Olivia Debiasse had approached the influential Wellesley family, during a family reunion, looking for her father, after the death of her mother. The brothers, Winston and Blake had been helping their father Casper Wellesley, with his political campaigning when both of them came in contact with the Olivia’s mother, Edna Debiasse. Once she realized that she was born 9 months after Edna had met the brothers, she worked out that one of them could be her father. Since the Wellesley’s mother didn’t want a scandal she told Winston to claim paternity, since Blake was running for the senate during that time. The detectives realized that Blake actually was actually Olivia’s father, as Winston being gay wasn’t even interested in Edna, thus reducing the probability of him being Olivia’s father. Winston was the only other person besides Blake who could have successfully claimed to be Olivia’s father, because of the sole reason that on the off chance that a DNA test was conducted, would match enough to convince Olivia that she was actually his daughter. This meant that no one would further investigate into the Olivia’s paterniy, if she was satisfied that she had found her father, but it was discovered because of her murder eventually.

 

 

Written by Eshani Singh (JGLS ’12)

Edited by Poulomi Bhadra

 

 

 

 

Advertisements

One comment

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s