Cynthia D Baga: The Coroner’s Court was told that no foreign or male DNA was detected on the biological specimens of the late Zara Qairina Mahathir, following a thorough forensic analysis by the Department of Chemistry Malaysia.
Chemist Nor Aidora Saedon, who conducted the analysis, said she examined 37 exhibits received from the police between August 11 and 20 to identify DNA profiles related to the deceased and any other individuals.
She explained that DNA can be transferred through contact with surfaces such as railings, depending on factors like the duration of touch, amount of sweat, and skin cell shedding.
“Trace DNA may be present through intentional or unintentional contact. However, it can completely disappear if the surface is cleaned or exposed to weather,” she said.
Nor Aidora, the 17th deponent in Zara’s inquest, testified that not all exhibits previously submitted for handwriting analysis, items Y2 to Y15, were provided for DNA examination. Only two items, exhibits Y1 and Y8, were tested for DNA.
She also explained that washing clothing greatly reduces the chance of recovering trace DNA.
“The probability of trace DNA surviving after washing is very low,” she said when questioned by counsel Rizwandean M. Borhan.
Results revealed Zara’s DNA profile matched completely with primary biological specimens tested, including tissue, bone, and bloodstains.
“No foreign DNA or significant male DNA was detected on any of the biological specimens, including swabs, fingernails, undergarments, and body samples,” she testified.
However, several personal belongings such as books, a bag, and a blanket showed mixed DNA profiles, which she described as inconclusive.
“These mixed profiles could have resulted from normal contact or shared use of items within the dormitory environment,” she added.
One key exhibit, marked ‘Y8’, which contained visible bloodstains, showed three DNA profiles, one major and two minor, suggesting the possible presence of more than one individual.
Nor Aidora clarified that analysis was limited to identifying the source of the blood, and no further testing was done on the minor DNA components due to their very low quantity, known as low-template DNA.
She also noted that DNA testing cannot determine the sequence of DNA deposition, so it is not possible to tell whether the blood appeared before or after other DNA traces on the same surface.
When asked by counsel Azhier Farhan Arisin if the minor DNA traces could result from ordinary environmental contact, such as shared books, Nor Aidora said yes.
She confirmed that the weak DNA traces did not affect her conclusion that the major DNA profile matched the deceased.
Nor Aidora agreed with counsel Azhier that despite minor background traces, the major DNA profiles remain scientifically reliable, conclusive, and consistent with Zara.
The inquest continues with the next deponent today (Wednesday).
