ENCYCLOPEDIA OF Espionage, Intelligence, and Security Volume ...

DNA FingerprintingAn FBI official holds a chart of the Combined DNA Index System (CODIS), a computerized database that allows law enforcement officers from around thecountry to compare DNA genetic evidence taken from convicted felons and gathered in unsolved cases. AP/WIDE WORLD PHOTOS.The DNA molecule contains all of the genetic informationfor every organism. Within a cell, DNA is organizedinto long strands called chromosomes. Every chromosomecontains many thousands of different genes. A geneis a functional segment of DNA that codes for a specificprotein. During protein synthesis, a portion of DNA istranslated into a complementary strand of ribonucleic acid(RNA), which is further transcribed into a sequence ofamino acids. A sequence of three nucleotides is requiredto code for one amino acid and chains of amino acids arefurther modified outside the nucleus of the cell into theproteins. There are approximately 50,000 different typesof proteins in the human body and they either performtasks or synthesize molecules required for the biologicalactivity that sustains life. The DNA in every individual,therefore, is the source of information the directs all of thebiological functions in the body.The DNA molecule is inherited by every cell and everyindividual. In asexual reproduction, the DNA in chromosomesis unwound and duplicated before the cell divides.Both daughter cells receive exact copies of the parentcell’s DNA. In sexual reproduction, a portion of the DNA isinherited from both the female and the male parent. Inhumans, there are 23 pairs of chromosomes in the genome.During meiosis, which forms the sex cells or gametes (theegg in females and the sperm in males), the chromosomalpairs separate and each gamete receives 23 unpairedchromosomes. When a sperm fertilizes an egg, its 23unpaired chromosomes are paired with the 23 unpairedchromosomes in the egg and the resulting zygote containsa unique set of paired chromosomes.SEE ALSODNA FingerprintingDNA Recognition InstrumentsDNA Sequences, UniqueDNA FingerprintingDNA fingerprinting is the term applied to a range oftechniques that are used to show similarities and dissimilaritiesbetween the DNA present in different individuals.336 Encyclopedia of Espionage, Intelligence, and Security