STR
STR stands for Short Tandem Repeat. It’s also the basis for almost all DNA testing as we know it. STR refers to whenever nucleotides (molecules which make up the structure of DNA when they’re joined together) create a pattern in successive sequences.
The pattern which nucleotides make can be as short as two pairs, or as long as ten pairs of nucleotides and by analysing and comparing these patterns laboratory technicians can create genetic profiles of people, such as those kept on file by the police, or compared in laboratories for genealogical purposes.
These STR patterns also come in useful for determining family ties because STRs from one DNA sample which match the STRs of another DNA sample signify that two people are biologically related. STR analysis is still quite a new science but it’s used around the world by laboratory workers in forensic departments to solve crimes and it is also a popular way to discover personal answers regarding paternity, maternity and other biological relationships. For example, if you didn’t know whether your mother was your true biological mother or not, a DNA test which compares your STRs with hers could prove whether or not the two of you share DNA.
In order to analyse STR patterns, lab technicians typically take nuclear DNA (from the nucleus of a cell) using a sample from the inside of a cheek, a hair or a blood sample. They then amplify and analyse the DNA using cutting edge techniques to identify sequences, before cross–referencing this information to answer questions.
