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Recent advances in forensic DNA testing are now paving the way for reforming the manner by which cases are resolved in courts of law through the way suspected offenders are apprehended during a criminal investigation. Firstly, the availability of new markers which are more variable across different populations, adds to the increased power of discrimination once more genetic markers are used. From the time when DNA testing only involved seven to nine genetic markers to evaluate if crime scene evidence matches a suspect’s profile, as well as to determine relationships, to the current battery of 21 autosomal markers and 23 male-specific markers, the capacity of DNA profiling to differentiate individuals has increased significantly. The use of automated and expert systems for large-scale analysis has also been found to reduce manual errors and to increase output per unit time. The use of several dyes in a single multiplex system provides more information from the same amount of genetic material compared to reactions targeting only one genetic marker but requiring the same amount of DNA that was common in the early 1990s.

Polymerase Chain Reaction (PCR) Analysis PCR analysis is a technique that allows technicians to create millions of precise DNA replications from a single sample of DNA. In fact, DNA amplification alongside PCR can let forensic scientists perform DNA analysis on samples that are as tiny as only a couple of skin cells. In contrast to some other DNA analysis techniques, PCR analysis has the advantage of analysing minuscule sample sizes, even if they are degraded although they must not be contaminated with DNA from other sources during the collection, storage and transport of the sample.

RFLP is a technique for analyzing the variable lengths of DNA fragments that result from digesting a DNA sample with a special kind of enzyme. This enzyme, a restriction endonuclease, cuts DNA at a specific sequence pattern know as a restriction endonuclease recognition site. The presence or absence of certain recognition sites in a DNA sample generates variable lengths of DNA fragments, which are separated using gel electrophoresis. They are then hybridized with DNA probes that bind to a complementary DNA sequence in the sample. RFLP was one of the first applications of DNA analysis to forensic investigation. With the development of newer, more efficient DNA-analysis techniques, RFLP is not used as much as it once was because it requires relatively large amounts of DNA. In addition, samples degraded by environmental factors, such as dirt or mold, do not work well with RFLP.

PCR Analysis Polymerase chain reaction (PCR) is used to make millions of exact copies of DNA from a biological sample. DNA amplification with PCR allows DNA analysis on biological samples as small as a few skin cells. With RFLP, DNA samples would have to be about the size of a quarter. The ability of PCR to amplify such tiny quantities of DNA enables even highly degraded samples to be analyzed. Great care, however, must be taken to prevent contamination with other biological materials during the identifying, collecting, and preserving of a sample.

Short tandem repeat (STR) technology is used to evaluate specific regions (loci) within nuclear DNA. Variability in STR regions can be used to distinguish one DNA profile from another. The Federal Bureau of Investigation (FBI) uses a standard set of 13 specific STR regions for CODIS. CODIS is a software program that operates local, state, and national databases of DNA profiles from convicted offenders, unsolved crime scene evidence, and missing persons. The odds that two individuals will have the same 13-loci DNA profile is about one in a billion.

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"The body chemistry of the person who left the fingerprint can tell us some things," said Shaler. "If the suspect is older or younger or a lactating mother, for example."The researchers used a form of physical vapor deposition -- a method that uses a vacuum and allows vaporized materials to condense on a surface creating a thin film. Normally, the deposition process requires exceptionally clean surfaces because any speck of dust or grease on the coated surface shows up as a deformity. However, with fingerprints, the point is to have the surface material's ridges and valleys -- topography -- show up on the new surface so analysts can read them using an optical device without the necessity of chemical development or microscopy."This approach allows us to look at the topography better and to look at the chemistry later," said Shaler. "We wouldn't have thought of this by ourselves, but we could do it together."One benefit of this approach would be the ability to retrieve fingerprints off fragments from incendiary or explosive devices and still be able to analyze the chemicals used in the device.The specific method used is a conformal-evaporated-film-by-rotation technique developed to create highly accurate copies of biological templates such as insect eyes or butterfly wings. Both are surfaces that have nanoscale variations."It is a very simple process," said Lakhtakia. "And fingerprints are not nanoscale objects, so the conformal coating is applied to something big by nanotechnology standards."

Investigators have found new DNA evidence in the murder of Peggy Hettrick, a case that was considered closed until genetic evidence freed a man who spent 10 years in prison, according to Colorado Attorney General John Suthers.The "touch DNA" tests weren't available in the late 1990s. Timothy Masters was convicted of murder in Hettrick's death in 1999, but his conviction was overturned in 2008 after defense lawyers used advanced DNA testing to uncover evidence suggesting a different suspect.The new evidence was taken from Hettrick's clothing. "We have done 'touch DNA,' and I think it has moved the ball forward. We will know more in the future," Suthers said. He wouldn't say whose DNA was found or identify the clothing on which it was found.Masters has not been exonerated in the case and remains a suspect."While we are not in a position to exonerate Tim at this time, I emphasize that he is presumed innocent and is no more a suspect than a variety of other people," Suthers said.