Criminalists use DNA___ in crime investigations.

Yes.

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Criminalists use DNA analysis in crime investigations.

To understand how DNA analysis is used in crime investigations, first, it is important to know what DNA is. DNA (deoxyribonucleic acid) is the genetic material found in almost all living organisms, including humans. It carries the biological instructions that make each individual unique.

When a crime is committed, criminalists collect various types of biological evidence, such as blood, saliva, hair, or skin cells, from the crime scene. These samples may contain DNA that could potentially link a suspect to the crime.

To analyze the DNA evidence, several steps are followed:

1. DNA Extraction: The first step is to extract the DNA from the biological sample. This involves separating the DNA from other cellular components.

2. DNA Quantification: The amount of DNA in the sample is determined to ensure there is enough for analysis. The quantity of DNA can vary, and it is crucial to have enough for reliable results.

3. DNA Amplification: Since the amount of DNA obtained from a crime scene is usually minimal, it needs to be amplified (increased) through a process called polymerase chain reaction (PCR). PCR makes millions of copies of specific regions of the DNA for analysis.

4. DNA Profiling: Once amplified, specific regions of the DNA, known as Short Tandem Repeats (STRs), are analyzed. STRs are regions of DNA that vary in length among individuals. By comparing the STR profiles of the crime scene sample with those of potential suspects, investigators can determine a match or exclusion.

5. DNA Database Comparison: If a match is not found among known suspects, the DNA profile can be compared to databases, such as the Combined DNA Index System (CODIS), which contains DNA profiles from convicted offenders and unsolved crimes. This comparison may lead to the identification or narrowing down of potential suspects.

DNA analysis is a powerful tool in crime investigations as it can link individuals to crime scenes, identify victims, exonerate the innocent, and provide valuable evidence in court. It has revolutionized forensic investigations and helped solve numerous cold cases through accurate identification and conclusive evidence.