User:Chawla55/sandbox

methods for early viral infection. The PCR is a powerful and practical research tool. The heretofore unknown etiologies of many diseases are being clarified by the PCR. The technique may enable the identification of previously unknown viruses related to those already known. If the proce dure can be further simplified and sensitive nonra diometric detection systems can be developed, the PCR will assume a prominent place in the clinical laboratory.

The research summarized here merely suggests the power of the PCR. Its power is, however, its own weakness. Even the smallest amount of contaminating DNA can be amplified, resulting in misleading or ambiguous results. To minimize the chance of contamination, investigators should reserve separate rooms for reagent preparation, the PCR, and anal ysis of product. Reagents should be dispensed into single-use aliquots. Pipetters with disposable plungers and extra-long pipette tips should be routinely used

Wooly mammoth mitochondrial DNA and DNA from brain of an egyptian mummy have been amplified and sequenced

the unpaired DNA strand onto the annealed primer. The number of DNA strands doubles upon completion of each cycle. After 30 cycles, a single copy of DNA can be increased up to 1,000,000 copies. In a sense, then, the replication of a discrete strand of DNA is being manipulated in a tube under controlled conditions

A primer is a single stranded sequence of nucleotides known as an oli gonucleotide. Each primer is complementary to one of the original DNA strands, to either the left (5') or right (3') side of the sequence of interest. The primers are present in such vast molar excess that they are more likely to anneal to the dissociated strands than the strands are to reanneal to each other