Microbiology: A Systems Approach 4th Edition by Marjorie Kelly Cowan

Exercise 36

Identifying the Victims of 9/11 Over a Decade Later
It has been over a decade since the terrorist attacks of 9/11/2001, and still the remains of many of the victims of the World Trade Center attacks have not been identified, leaving families and loved ones with unresolved grief. As of September 2011, 1,632 victims had been identified and 1,121 had not. The positive identifications were achieved mainly through DNA analysis of 21,800 body parts recovered from the site. Fire from the explosions, steel, concrete, glass, and water used to douse the flames all contributed to the degradation of the remains, making DNA extraction extremely difficult. Many of the remains were so badly damaged that there was little to no genetic material for analysis.
Relatives of the victims soon began to provide DNA samples to the newly developed Mass Disaster Kinship Analysis Program (MDKAP). These donated samples were used to create a database that would facilitate the identification of lost family members. Families gave hair, toothbrushes, razors, or other personal effects of the victims that contained their DNA to the MDKAP. Using the DNA extracted from these samples, forensic scientists were able to identify some of the unknown remains by scanning the MDKAP database for genetic similarities. The quest to identify the victims of the WTC attacks has spurred innovations in DNA analysis that have been helpful in identifying other individuals such as missing persons or war casualties.
How is DNA from the victims of the WTC attacks analyzed
What improvements to this technology have been made in the past decade to accurately identify the victims
Source: L. Geddes, "Massive DNA Effort to Name 1121 Unknown Dead of 9/11," New Scientist 2829 (2011). Retrieved from www.newscientist.com/article/dn20878-massive-dna-effort-to-name-1121-unknown-dead-of-911.html.2011. New Scientist. vol. 2829, p. 7.
When a piece of DNA is analyzed through the process called polymerase chain reaction (PCR), primers-short strands of DNA-attach to the target DNA in order to make multiple copies for analysis. If the DNA is badly damaged, as is the case with the WTC remains, the large DNA primers do not stick to the DNA strand and it cannot be amplified. This problem spurred scientists to look for smaller pieces of DNA called short tandem repeats (STRs) that could be more easily amplified. These STRs are patterns of two to five nucleotides repeated directly adjacent to each other on the DNA strand in a pattern such as this, "GATAGATAGATAGATA." These repeated sequences are unique to each individual and when these regions are compared against a database of STRs (such as in the MDKAP), a match can be made. The push to identify the degraded DNA from the WTC site spurred scientists to find more effective ways to analyze STRs. The result was a product called the MiniFiler kit that can amplify even very small pieces of DNA for analysis. This product is now used worldwide in identification of disaster victims in addition to the WTC victim samples.
What other methods have been recently discovered to improve the identification of WTC victims