We're constantly amazed by what we can get DNA off of , said Joseph Galdi
, supervisor of the Suffolk Crime Lab's biological sciences division.
Scientists recently swabbed the inside of a glove left at the scene of a burglary and were able to get a full DNA profile , Galdi
said.And in the case of Kristin Scarabelli , authorities say the new DNA testing method linked next-door neighbor Stephen Manolis to an object found on her
front lawn , where police say she
DNA tests available when she
was killed five years ago could not have revealed the same information , forensic scientists said.
Crime scene investigators have relied on DNA evidence - sometimes called genetic fingerprinting - for more than a decade.The idea behind it is that DNA , the unique biological code found in the cells of every person , can be used to match blood stains , semen or saliva found at a scene or on evidence to a suspect or a victim.
Until two years ago , forensic scientists used two kinds of DNA tests , each with its own trade-offs.Restriction fragment length polymorphism , or RFLP , testing offered accurate results , but it was time-consuming and required a relatively large stain - about the size of half a dime , Galdi
The other method , polymerase chain reaction , or PCR , could be performed quickly on a much smaller sample but was less accurate.
The new method , short tandem repeats , or STR , offers the best of both methods.It is accurate enough in many cases to make a virtual match between a DNA sample and a specific person , even while using a tiny piece of evidence.