The chief analyst of the DNA report which ruled out a link between G Sara Lily and the body she claims to be that of her son, defended the analysis.

Despite her own admission that there had occurred degradation and 'imbalances' among other concerns during the DNA profiling exercise, Dr Chang Yuet Meng said these did not affect her final analysis.

Chang, who heads the DNA laboratory at the Department of Chemistry where the analysis was conducted, was testifying in a judicial inquest to determine if the body lying in the Universiti Malaya Medical Centre morgue is that of missing police detainee G Francis Udayappan (photo).

Chang said she was certain that no contamination had occurred during the extraction and quantification of the DNA sample acquired from the bone marrow of the body fished out from the Klang river on May 23, 2004.

In response to questions from Sara Lily's counsel M Puravelan, she said this was because the chemicals and instruments used were "autoclaved (sterilised) before being used" and "discarded after being used."

Even the centrifuge tubes used in the separation of the solution containing the DNA specimen are "wiped down with decontaminating agent" prior and after use, she told Kuala Lumpur magistrate Mohd Nazran Mohd Sham who is acting as coroner in the inquest.

"In the autoclaving environment in our laboratory, there is no contamination. I say this because in our own lab we have quality check procedures," she added.

Other 'concerns'

However, Chang admitted that she had noted in the report "signs of degraded DNA" in the bone-marrow sampling she received but this did not affect her interpretation of the facts.

At this juncture, Puravelan questioned her on the other "concerns" that he said were present in her recording notes, such as "loci imbalance".

"Out of all eight concerns, degradation, pullouts, stutters, mixture, allele drop-outs, loci imbalance, all of these are there (in the DNA profiling), aren't they, Dr Chang?" he asked.

Chang maintained that such concerns did not conclusively affect the report.

"Not all the concerns are there, no. They cannot confirm conclusively. Stutters are inherent in all DNA profiling," she said.

"Interpretation is subjective, but it has to be based on the raw data and (established DNA profiling) guidelines," she added.

Francis, 24, was said to have escaped from the Brickfields police headquarters nearly two years ago by jumping into the nearby Klang river.

However, his mother consistently maintained that he had been assaulted and dumped into the river by the police.

A police investigation later ruled out any possibility of foul play but this did not convince Sara Lily, who insisted that the highly decomposed remains in the morgue is that of her son based on a tattoo and teeth deformity.

Magistrate Nazran fixed the next hearing for Feb 27.