Forensic+community's+reponse+to+sept.+11+Case+Study+SES

OCME: office of Chief Medical Examiner - perform varies tasks, including examining physical evidence; conducting DNA extractions; and overseaing DNA quantitation, amplification, and finally, DNA typing - normally handle sexual assaults, homicide etc but in the case of the WTC they also had to determine the cause of death. They couldn't do both so they contracted out the DNA typing work.

Due to the smoldering fires, the exposure to the outside weather, and the estimated amount of time it would take to remove the debris ( a year) presented alot of problems for chemists.

- the bodies were taken to Fresh Kills a "reincarnated landfill, the country's largest rake nad sift DNA lab." - workers picked through concrete, rocks and other rubble looking for human tissue, teeth and even hair to aid in the identification process. these extracts are then shipped off to the respective companies for DNA typing and profiling.

(STR is a technique that focuses on 13 loci found over the 23 pairs of chromosomes that make up a human's genome)

- when hair skin and other tissues arent available chemists must turn to bones. BODE technical group oversaw the bone analysis of the victims. - BODE' s lab had about 70 employees and one of its 2 specialized is devoted to forensic analysis

- when tissue samples are severely burned or degraded, a process called mitochondrial DNA (mtDNA) analysis often has to be done

- After DNA profiles are obtained, the results are then shipped back to New York State Police Lab where the information is stored in a specially modified verson of the FBI's Combined DNA Index Systems (CODIS) database

-CODIS originally stored DNA info of convicted criminals and is used to match the info in prosecution cases. - the new version uses the same DNA comparison software, but only to match the Sept. 11 DNA profiles to those of the recovered victim's blood samples submitted by their relatives, and to the DNA info obtained from their toothbrushes, hair, soiled laundry etc.

-The condition of the recovered body parts determines which type of analysis- nuclear (nucDNA) or mtDNA- is performed.

-nucDNA analysis is most commonly used because its faster, the genome is found in the cell's nucleus, and the DNA has alleles from each parent.

- in nucDNA analysis: - the DNA fragments are analyzed and amplified using PCR. - the profile from the nucDNA is obtained and used to match and verify a victim. ( requires alot fo sample) - PROBLEM: despite having a large amount of sample, sometimes there are only 3 grams of usable tissue that can be alalyzed

-in mtDNA, mitochondria are abundant in the cell's cytoplasm, but the mtDNA only comes from the mother. - high number of mtDNA genomes in the cell increases the likelihood of successful PCR amplification. - more difficult to perform, more time consuming, and expensive.

- Smith learned that they found that by having a DNA collection team at the crash site, that they could collect the tissue sample after it has been taken from the body and tag it with a number and bar code onsite before it gets back to the lab.

- Today most labs use PCR to analyze DNA.