Blog

Solving crimes and mysteries

Apr 11, 2015 | Science and Technology

A large portion of human DNA does not code for genes (units of DNA that contain instructions for creating proteins). These non-coding regions nevertheless contain much information useful for forensic and other human identification applications. Non-coding regions of DNA contain many of the markers used for identity testing.

  • Short tandem repeats (STRs) are sequences of DNA that are 2-6 base pairs long. The number of repeats in STR markers is highly variable among individuals, which makes STRs useful in human identification. STRs are used to create the genetic profiles that help to identify criminals, prove paternity and other family relationships, and identify remains found in a disaster area.
  • Mitochondrial DNA (mtDNA) is found in the energy-producing organelles of the cell called mitochondria. Most of human DNA is found in the nucleus in two copies (nuclear DNA, which is routinely used for STR typing). Mitochondrial DNA, on the other hand, is a shorter piece of DNA found in hundreds or even thousands of copies per cell. Analysis using mtDNA finds its most use in forensics, when there is very little sample available.

    Non-coding regions in mtDNA, called hypervariable regions, have significant sequence differences that can be used to differentiate two unrelated individuals. In contrast, biological relatives have the exact or very similar sequences at this region. Mitochondrial DNA is inherited through the mother, and the biological relationship of two or more individuals may be determined by examining their mtDNA sequences at the hypervariable regions.

    Mitochondrial DNA testing was used to identify the bodies of the Romanovs found in a burial site in Yekaterinburg, Siberia. Mitochondrial DNA sequences from a maternal relative, Prince Philip, matched the DNA extracted from the remains of the Tsarina and her daughters; mtDNA sequence from the Duke of Fife (a maternal relative of the Tsar) was used to confirm the identity of the Tsar’s remains.

  • Y chromosome typing (Y-STR) uses short tandem repeats found on the Y chromosome to trace the ancestry of males through the paternal line. The Y chromosome is only passed from father to son, relatively unchanged through the generations, and thus males related through a paternal line share the same Y-STR pattern. While Y-STR analysis gives clues about males’ recent ancestry, another type of markers called SNPs (pronounced “snips,” single nucleotide polymorphisms) give clues about deep male ancestry—the early origins of the different human populations, going back even up to 100,000 years. Analysis of SNPs combined with Y-STR typing is used to recreate historical migrations of waves of populations across the world.

For more information about DNA application in solving crimes and mysteries, visit DNA Interactive: Applications.

0 Comments

Submit a Comment

Your email address will not be published.

Staff Publications

[ultimate_spacer height="30" height_on_tabs="20" height_on_tabs_portrait="20" height_on_mob_landscape="10" height_on_mob="10"] DDC scientists have published a...

How DNA Testing Has Changed

1920s - Blood Typing In the early 1900s, scientists identified 4 different blood types in humans - A, AB, B, and O - based on the presence of certain proteins called antigens in the blood. This blood typing system, called the ABO system, provided doctors with crucial...

How Long Does Immigration Testing Take?

DNA testing is often required in immigration cases where a U.S. citizen is sponsoring the immigration of a relative and needs to prove to the U. S. Customs and Immigration Service (USCIS) or U.S. embassy or consulate that the person seeking to immigrate to the U.S. is...

What Do I Do with the Results of the DNA Test?

The results of your ancestral DNA tests can be used in a few different ways. Of course, the test will verify biological relationships you uncovered in your research. After DNA testing you will know that you are (or are not), in fact, biologically related to the family...

Reach Us

Have questions or need assistance? Contact our team.

DNA Technology Park
1 DDC Way
Fairfield, OH 45014

USA:
INT: + 1.513.881.7800

Leave A Message

!---->