Types of DNA Analysis

A process of conducting a study about genetic sequences, DNA analysis is being used by medical personnel and law enforcement agencies to identify a particular species or person. It can even be used to determine specific diseases and cancers. At one point, this process becomes very limited. However, DNA is now analyzed using numerous processes.
The forensic DNA analysis comes in three different types: Y-Chromosome, STR or Short Tandem Repeats (uses PCR or Polymerase Chain Reaction), and mtDNA or Mitochondrial DNA.
Y-Chromosome Analysis
The Y chromosome is very useful in forensic applications as it helps identify the suspects. This chromosome can only be found in males and can only be passed down from a father to a son. Hence, analyzing this chromosome separates the female DNA and identifies familial relationships. Another advantage it offers is its ability to limit the pool of potential suspects even if there are numerous male contributors found in the biological sample. With the latest advancements, the process of extraction that is used to separate the vaginal cells from the semen prior to the DNA analysis becomes unnecessary.
Short Tandem Repeat or STR Analysis
Short Tandem Repeat or STR analysis examines the particular areas or loci in the nuclear or normal DNA. Each person comes with a distinct region of DNA. This process improves the difference of one DNA profile from the others. In cases of identical twins, the chances of two people sharing similar 15-loci profile is still one in a 1,000,000,000,000,000,000,000,000,000.
The FBI (Federal Bureau of Investigation) set a standard of 13 STR loci for the STR analysis and for DNA databases. This is to ensure that all forensic labs will have the ability to share and use the same forensic information. The CODIS database for unsolved cases creates profiles using the STR process, according to the 13 STR loci guideline set by the FBI.
Mitochondrial DNA Analysis
The mtDNA or Mitochondrial DNA analysis is used to examine samples that cannot be analyzed through an STR analysis due to non-availability of a nucleic DNA material. This type of analysis uses a DNA that is taken out from the mitochondrion. Unlike the STR analysis that uses the cell's nucleic DNA, the mtDNA extracts DNA from old sample evidence such as bones, teeth, and hairs that no longer have any nucleic DNA material. The mtDNA analysis is an extremely beneficial process to help solve unidentified remains and cold cases.
Though the STR analysis can also be used in creating DNA profiles from an old evidence, but the sample materials like semen or blood are sometimes destroyed in the PCR testing while generating an accurate profile. Nonetheless, the Mitochondrial DNA analysis can be used to examine an old sample material like a hair shaft and eventually helps solve the case. Furthermore, the mitochondrial DNA is only passed down from the mother to all of her offspring. Hence, everyone related to the mother has the same mitochondrial DNA.