DNA Forensics: Unraveling Crime Scenes with Genetic Evidence

Study Notes

DNA Forensics: Unraveling Crime Scenes with Genetic Evidence

DNA forensics, also known as molecular biology in forensic science, revolves around the examination and analysis of deoxyribonucleic acid (DNA) to solve criminal investigations, identify missing persons, and provide evidence in legal disputes. In this article, we'll delve into the core aspects of DNA forensics, exploring key subtopics like gel electrophoresis, base pairs, the location of DNA, DNA profiles, the Combined DNA Index System (CODIS), and DNA fingerprinting.

Gel Electrophoresis

Gel electrophoresis is a laboratory technique used to separate DNA molecules based on their size. This technique separates DNA fragments by applying an electric field across a gel matrix that resists the movement of larger molecules. The process results in bands that represent the distinct sizes of the DNA fragments, and these bands can be visualized and analyzed.

Base Pairs

DNA is a long, double-stranded molecule that is composed of four different nucleotide bases: adenine (A), guanine (G), cytosine (C), and thymine (T). These pairs (A-T and G-C) bind together in a specific sequence known as the DNA strand. The sequence of these base pairs forms the genetic code that is unique to each individual.

Where DNA is Located

DNA is found in the nucleus of eukaryotic cells, including those in humans and other animals. The DNA molecules are tightly coiled around proteins called histones to form structures called chromatin. The chromatin further condenses into chromosomes, which contain the genetic material necessary for an organism's development and functioning.

DNA Profiles

A DNA profile, also known as a DNA fingerprint, is a unique genetic blueprint that reflects the specific sequence of an individual's DNA. DNA profiles are generated using specific genetic markers, known as short tandem repeats (STRs). STRs are segments of DNA that are repetitive and vary in the number of times they occur in a given individual's genome. These variations allow scientists to distinguish between individuals and create a DNA profile that can be used as evidence in forensic investigations.

CODIS

The Combined DNA Index System (CODIS) is a national database that stores DNA profiles obtained from crime scenes and arrestees. CODIS enables law enforcement agencies to compare and analyze DNA profiles to identify suspects, match evidence to criminal profiles, or verify the identity of victims. CODIS also allows for regional, state, and national searches, as well as international exchanges to solve transnational crimes.

DNA Fingerprinting

DNA fingerprinting is a technique that uses specific genetic markers (STRs) to generate a unique DNA profile. This method was first developed by Sir Alec Jeffreys in 1984 and has since been widely used in forensic science, paternity testing, and other fields. DNA fingerprinting can help to identify or exclude suspects, determine the sexual assault perpetrator in rape cases, and provide evidence in other cases where conventional forensic methods cannot.

DNA forensics is a rapidly developing field that holds the potential to revolutionize the way we solve crimes and identify missing persons. The techniques and methodologies described here form the backbone of modern forensic science, and they have helped to improve the efficiency and accuracy of criminal investigations.

Description

Explore the world of DNA forensics, which involves analyzing DNA to solve criminal cases, identify missing persons, and provide legal evidence. Learn about key concepts like gel electrophoresis, base pairs, DNA location, DNA profiles, CODIS, and DNA fingerprinting.