Forensic Dentistry at its best

The time has come once again, for us to enlighten you on the developments of this mysterious case. We know you’re excited to see us again (hopefully) . So, sit back and enjoy the ride as we guide you through another part of the assignment(Part 3) =D

             

We shall start off with question 5 of part 3.

In this question we were asked to match the photos of the victims’ pieces of evidence and explain our rationale for doing so.

Hence, below we have posted the picture of evidences that were gathered, followed by our analysis of the structures in each picture and how it helps us determine the victims.


Picture 1: Adult 's skull & jaw

Skull: 

• Large (Adult skulls are generally larger in size compared to children)

Temporal process of zygomatic bone : 

• More prominent ( Temporal process of zygomatic bone is more prominent in adults)

Orbits:

• Squarish with roundish margins ( Males tend to have a blunter, more rounded surface here, females a sharper border. Hence, indicating the evidence belongs to a male victim)

Dentition:   

• 8 alveolar processes of the mandibular arch in each quadrant.  (Adult have 8 alveolar processes in each quadrant while children have 5)
• A third molar at quadrant 4. (The eruption date of mandibular 3rd molars are between 17-21 years old. Hence, the victim's age would be at least 17 years old if not older)

Based on the Picture 1, we can deduce that the evidence possibly belonged to Herman Hartono or his son(Adi Hartono), both whom lived near the scene of the crime and have been reported missing.

Picture 2: Pieces of a jaw

Picture 2 showing a piece of broken jaw of an adult bearing the permanent mandibular 1st, 2nd and 3rd molars.

Mandible:

• Angle of mandible is more acute (Indicating it’s a male victim as angle of females are usually more obtuse to the lower jaw bone)

Dentition:

• All 3 molars are present, i.e. 1^st, 2^nd and 3^rd molars

This is because the 3 molars can be easily distinguished from other teeth due to their features which are:

Permanent mandibular 1st molar:

• The root bifurcation mesiodistally
• Crown taper from buccal to lingual  
• Central groove zigzag mesiodistally

Permanent mandibular 2nd molar:

• 4 cusps 
• Straighter central groove
• Crown wider mesiodistally than faciolingually
• Lingual groove and buccal groove align to intersect with central groove like a '+'

Permanent mandibular 3rd molar(eruption date after 17 years old):

•  Smaller crown, smaller occlusal table compared to permanent 1st and 2nd molar
•  Resemble permanent 2nd molar but smaller
•  More rounded outline (occlusal aspect), bulbous appearance 
•  4 cusps

Since 3rd molars are only present in adults, this jaw may also belong to Herman Hartono or his son, Adi Hartono. At this point, there is insufficient information to determine the exact ages of both sets of evidence and hence match them directly to the victims. However, it is safe assume that the younger male victim(possibly Adi Hartono) is at least 17 years old. 

Picture 3: Child's jaw

Jaw: 

• Small in size (Children’s jaws are generally smaller than those of adults)

Dentition (Permanent mandibular canine):

From the picture given, its difficult to accurately identify if the canine present in the jaw is deciduous or permanent. However, based on our analysis, we strongly believe it’s a permanent mandibular canine. This is because:

-   the permanent mandibular lateral incisor is in the process of eruption (this tooth erupts at age 8-9 years as well) hence providing evidence that the canine present is likely to be a permanent one.

The presence of this permanent mandibular canine in the jaw also provides a possibility that the victim may indeed be Anya Rosilawati as she is 9 years old and both these teeth(permanent mandibular canine and permanent mandibular lateral incisor erupt at her age).

Mandibular angle:

• Obtuse angle ( More acute in adulthood or male, hence indicating that the victim is likely to be female)

Chin:

• More pointed chin ( Female mandible tend to have more pointed chin while male mandible have a square shape) 

Therefore, we can conclude that the jaw belonged to a child who might be Anya Rosilawati (9 years old)- who is filed missing 4 months ago.

The power of DNA profiling (editted)

Before proceeding to question 6, lets run through some facts about TWINS, since its relevant to our currrent stage in the mystery.

According to medical dictionary, monozygotic twins or identical twins are two individuals developed from one fertilized oocyte; hence, they have identical genomes.

How does this happen?

Comparison of zygote development in monozygotic and dizygotic twins

Identical twins are formed after a blastocyst essentially collapses, splitting the progenitor cells (those that contain the body's fundamental genetic material) in half, leaving the same genetic material divided in two on opposite sides of the embryo. Eventually, two separate fetuses develop.

Fun fact (well..kind of)

Spontaneous division of the zygote into two embryos is not considered to be a hereditary trait, but rather a spontaneous or random event. Monozygotic twins may also be created artificially by embryo splitting.

       

                         Embyo splitting 1                                          Embryo splitting 2

Genetic similarity: 

1. Identical twins do not have the same fingerprints, due to the fact that even in a small space inside the womb, people have contact with different parts of this environment, which gives small variations in the same digital, making them unique
2. Monozygotic twins are genetically nearly identical and they are always the same sex unless there has been a mutation during development. 

DNA patterns from four sets of twins 

Our DNA also changes in response to things like sunlight or the food we eat. Both can damage the DNA causing mistakes to happen. All of the changes aren't in all of our cells -- not all of our cells have the same DNA sequence! If a DNA mistake happens late in our development, then only a few cells will have that mutation. If a mistake happens early, then more cells will have the DNA change but still not all of them. Such mutations, however, are normally so tiny that DNA analysis can't detect them.

With the technology that we have currently, the police are unable to determine which twin was involved with  the crime. So what do the police do?

Well, police don't use DNA analysis since the DNA is the identical, hence police dust for fingerprints.

Comparison of palatal rugae patterns in siblings and twins

Comparison of palatal rugae patterns in siblings, twins and parents revealed no similarity of rugae patterns. This suggests that there is no evidence of rugae pattern features inheritance. Similar results were given by Fahmi et al (2001) who reported that no two palates are alike in their configuration. Even between twins, the patterns are not identical.

Science of lip prints is called cheiloscopy.

Japanese doctor Suzuki is supposed to have done the greatest work on lip prints. In 1970, he recalled the attention of everyone on the fact that the possible use of lip prints in personal identification. He examined 18 pairs of uni-ovular twins aka identical twins and found that there were considerable similarities in these twins. Before proceeding further, it would be proper to explain briefly about uni-ovular twins. These twins were initially conceived as a single individual from a single ovum, they are called uni-ovular twins. They are always of the same and are very much similar in appearance. It is in the light of these facts that Professor Suzuki was studying lip prints. But of the 18 pairs of uni-ovular twins that he studied, he found remarkable similarities. This was somewhat depressing for the forensic scientists although quite predictable.

             However MacDonell in 1972 described two identical twins who seemed to be indistinguishable by every other means, but lip prints in these twins differed. This was interesting news as identical twins had not been distinguished before by lip prints. He could differentiate between them by some other methods too. These were fingerprints, handwriting, voice prints and nail clippings.


Moving on to the question, 

The question is as follows:
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.

Picture 1: Adult’s skull & jaw

Picture 2: Pieces of a jaw

Picture 1 and 2 shows two adult remains and along with DNA profiling evidences, we can deduce that they are father and son. Thus, the remains most probably belong to Herman and Adi.


Picture 3: Child’s jaw

Picture 3 will then belong to Anya since the DNA profile matches the living sister, Tanya.
Since both of them are identical twins, meaning they come from the same fertilized egg, which had only one complete set of DNA in the first place. That fertilized egg and its single set of DNA split to form twin embryos-each with its own set of DNA, identical to the other.

So, that marks the end of another week. Only one week to go =D