Who's Got A Match?

Today, we shall tackle Question 6 which requires you to match the evidences collected with the missing people's DNA samples. 

Question 6 

The DNA profile showed evidence for a father and son. In addition there was DNA profiling pattern that matched one living twin (Tanya Rosilawati). With this, match the evidence to these victims who were earlier filed for missing persons. Explain your rationale.

Remember the bone remains and skull fragments you have collected from the crime scene? Well with those evidences, you're surely going to identify them by DNA profiling. Read this DNA profiling before you start your matching process :)

From the bone remains, DNA traces are extracted and collected. Assuming you have some DNA samples with you, how are you going to find out whether this person's DNA shares a relationship with another person's? The DNA sample you have from the crime scene, is it the same as the missing person's DNA or the victim's?

* Note : All characters in this publication are fictitious and any resemblance to real persons, living or dead, is purely fictional. All photos published are credited and used solely as examples. All DNA samples are purely fictional.

Let's start off our matching process :) and assume you have all the evidences you need.

Imagine, you're in the forensic lab now working on DNA samples. 

We shall look into Adi Hartono and Herman Hartono whose names are in the list of missing people. We know they are son and father respectively, but let's allow DNA to prove us that!

Picture adapted from : http://www.tumblr_lrj3btIopM1qeogk0o1_500

DNA sample from
a young male
adult's bone

From the crime scene, you found a DNA sample from a male young adult's bone remains :

The DNA sample on the left is from a MALE YOUNG ADULT. Next, check the list of missing people. Who could be the potential owner to this DNA sample?

Of course, it would be ADI HARTONO. Now, we cannot be entirely sure if this belongs to Adi because we know it is from a male young adult but it doesn't mean it has to be Adi ; it can be from any male young adults whose names have not been listed down. 

So, in order to confirm our hypothesis, we shall extract Adi Hartono's DNA from anything that belongs to him such as hair, saliva, skin, blood and even semen too. Forensic investigators may collect these evidences from Adi's room or may be from his family doctor who has his blood samples.

Assuming, you have finally determined Adi's DNA sample from his hair, let's compare the DNA sample from the crime scene with the DNA sample from Adi's hair :

Voilaaaa ! It is a MATCH ! 100% match ! So, you can confirm that the bone remains of the male young adult belongs to Adi Hartono and you may rule out other potential male young adults.

Picture adapted from : http://www.facebook.com/l.php?u=http%3A%2F%2Fwww.ibtimes.com%2Findonesia-smoking-itself-death-782831&h=OAQEOE59m

DNA sample
from a male adult's
bone

Now, let's move on to the DNA extracted from the male adult's bone remains. Could it be Adi Hartono's father? Let's find out if the bone remains belong to Herman Hartono whose name is also on the list of missing people.

On your left is the DNA sample from a MALE ADULT.

Assuming that you have conducted the same procedure as you have with Adi Hartono ; collecting DNA sample from Herman Hartono's hair and match the DNA sample on your left with the DNA sample from Herman's hair. If both DNA samples match each other, it means that the bone remains belong to Herman Hartono. 

Now, here comes the tricky part. In order to confirm again that the male adult's bone remains belong to Herman Hartono and also to find out if Herman Hartono and Adi Hartono are blood-related, you will need to compare Adi's DNA sample with Herman's DNA sample.



Let's compare !

Here, you have 3 DNA samples. Observe carefully and try to determine if these DNA samples are related to one another. From left to right, Adi Hartono, Herman Hartono and Ms.Hartono (Herman's wife/Adi's mother). You need to find out if Adi Hartono is the son of the Hartono family. 

Looks like it is a match ! So Adi Hartono is related to Herman Hartono and Ms.Hartono by blood and it can be comfirmed that Adi is their son. Hence, the male adult's bone remains belong to Herman Hartono!

 Observe carefully at the DNA bands which look like a bar code. Compare the 3 DNA samples and you will find the similarities.

From your observation, you will be able to find that some of the DNA bands from Adi match with Herman's DNA bands and the rest of Adi's DNA bands match with his mother's DNA bands. It can be concluded that all DNA bands inherited in a child's profile are inherited from his parents.

Here are the basic steps to determine paternity.

Steps to Determine Paternity

1. Begin with the known parent. Assign the known parent a color, blue for instance.
2. Color all of the known parent's bands blue.
3. Look at the first nestling (n1). Color all of the bands from the nestling (n1) that exactly match a band from the known parent, blue.
4. Look at the remaining adult individuals. Assign each one of them a different color, green and yellow for instance.
5. Color all of an adult's band his/her assigned color.
6. Look at the nestling's remaining bands. They must have been contributed by the second parent. Compare these bands to the remaining adult individuals. Find the adult which contains ALL of the remaining non-colored bands in the nestling's profile.
7. Color the identifying bands in the nestling the same color as the second parent's bands.
8. Repeat steps #3, 6 and 7 with the remaining nestlings.

After solving the mystery of the father and son, now let's move on to one of the missing twins. In order to investigate and match the DNA profiles of twins, you first need to understand the difference between identical and fraternal twins. 

Picture adapted from http://www.genomesunzipped.org/2010/12/estimating-heritability-using-twins.php

Identical or monozygotic twins develop from one egg fertilized by one sperm which later split to form two embryos. Thus, they share the same genetic profiles. On the other hand, fraternal or dizygotic twins develop from two eggs fertilized by two sperms. Hence, they have different genetic makeup. Fraternal twins are just like individual siblings born at different times. 

Picture adapted from http://www.tumblr.com/tagged/twin%20girls?before=1344527367

From the missing persons’ list, Tanya Rosilawati’s twin, Anya Suriati, has been recognized as one possible victim of this murder case. We know that the DNA profiling pattern of one possible missing victim matched Tanya Rosilawati, so let’s compare their DNA profiles.

As we can see, these two DNA profiles match each other at all bands. So we can safely conclude that the child’s jaw remains belong to the missing person Anya Suriati, who is also Tanya Rosilawati’s identical twin!

Fun Facts about GENES! 

Theoretically, identical twins develop from monozygotic cell division will share the same genetic profile. However, science and technology in this 21^st century has proven it to be not quite accurate in some cases. 

In February 2008, geneticist Carl Bruder of the University of Alabama at Birmingham, reported results of a study of nineteen identical twins.  Bruder and his team discovered relatively common, but small, differences in the DNA of these identical twins.  What happens is one twin’s DNA differed from the other at various points on their genomes, i.e. one twin had a different number of copies of a given gene than his twin.  This genetic state is known as 'copy number variant' or CNV. 

How is it so? At first when the fertilized egg is divided into two, identical genetic profile of 100% similarity is seen. The initial divided fertilized egg will form two cells which mean at the beginning the DNA is identical. However, in order for the egg cell to form into embryo, millions or even trillions of cell division must occur. In between the process of cell division, the cells can make mistakes in the number of copies of a given gene passing to the daughter cells, which is the so-called mutation.  However, such mutation could not actually being spotted upon DNA analysis. Hence, that’s how twins sometimes can reach different numbers of copies of a gene and why some identical twins’ DNA are almost identical but not fully identical.

Picture adapted from  http://www.wonderquest.com/twins-dna.htm

As you can see in this picture, you can note the slight difference between each twins’ DNA profile. For individuals in B and C, you can see that there are more similarities in the DNA profiling whereas sometimes due to CNV, you can expect results in A and D. 

Hence, for Tanya Rosilawati and Anya Suriati’s case, you can see the similar patterns of theirs as in B and C.

Cheers!

References:

http://biology.arizona.edu/sciconn/lessons2/vuturo/vuturo/add_info.htm

http://www.livescience.com/4833-identical-twins-dna-varies.html

http://www.wonderquest.com/twins-dna.htm

http://www.homednadirect.ca/dna-news/twin-dna-testing-murder-case-ronald-donald-smith.html