ABSTRACT
Every pa rt o f t he D NA i n t he c ell c arries w ith i t a u nique reverse complement. When the two strands unwind, the molecular machinery of the cell can build a new perfect copy of each strand using the opposite strand as a template. e property of complementarity also makes DNA an excellent target for molecular a ssays. F or a ny s trand o f D NA a bove a c ertain leng th, a unique mole cular p robe c an b e de signed, w hich w ill b ind, o r hybridize, o nly to i ts c omplementary t arget. I f t he p robe i s labeled using a radioactive or uorescent tag, the presence of the target c an be co n rmed. e c omplementarity o f D NA a lso allows for a c hain reaction of a mpli cation. In t he presence of appropriate amounts of enzymes, free nucleotides, and short oligonucleotides called primers, the polymerase chain reaction will faithfully reproduce a s equence of DNA along with its complement, making massive quantities of a particular sequence available for use in molecular biology experiments.
