الفهرس | Only 14 pages are availabe for public view |
Abstract DNA is the genetic material that determines individual characteristics that are faithfully transmitted from parent to offspring. DNA is packaged into chromosomes that reside in the nucleus of individual cells. During each cell division these chromosomes replicate and divide, ensuring that the two daughter cells receive DNA content identical to that of the parent cell. DNA fingerprinting is a powerful technology that has revolutionized forensic science. No two individuals can have an identical DNA pattern except identical twins. Such DNA-based technologies have enormous social implications and can help in the fight against crime. This technology has experienced many changes over time with many advancements occurring. DNA testing is a matter of serious concern as it involves ethical issues. Eukaryotic genome contains repeated DNA sequences which come in different types of sizes, and collectively referred to as variable number of tandem repeats (VNTRs). They are typically designated by the length of the core repeat unit and the number of contiguous repeat units. DNA regions with repeat units of 2-6 bp in length are called microsatellites or short tandem repeats (STRs). The number of repeats in STR markers is highly variable among individuals, making these markers effective for human identification purposes. They are scattered throughout the genome. The small size of STR alleles compared to minisatellites makes STR markers better candidates for use in forensic applications. Polymorphic STR loci can be copied simultaneously by multiplex PCR using fluorescently labeled primers. |