Virus and spyware definitions are files that act like an encyclopedia of known malicious software, including viruses, spyware, and other potentially unwanted software.
Highly accurate DNA parental testing became available in the 1980s with the development of RFLP. In the 1990s, PCR, developed in 1983, became the standard method for DNA parental testing. A simpler, faster, and more accurate method of testing than RFLP, it has an exclusion rate of 99.99% or higher.
A brief treatment of DNA follows. For full treatment, see genetics: DNA and the genetic code. The chemical DNA was first discovered in 1869, but its role in genetic inheritance was not demonstrated until 1943. In 1953 James Watson and Francis Crick determined that the structure of DNA is a double-helix polymer, a spiral consisting of two DNA strands wound around each other.