Question

PCR amplification of DNA is a useful technique when

there is limited sample.

there is abundant sample.

there is no other evidence.

contamination of evidence occurred.

dental evidence is excluded.

Answer 1

Answer: there is limited sample.

Step-by-step explanation:

Polymerase chain reaction is a technique that is used for amplifying samples of DNA in vitro. This technique was discovered by Kary Mullis. It can be useful for producing multiple copies of DNA available in very low amounts. It can amplify genomic DNA 50- 250 ng and 1-10 pg for viral or plasmid DNA.

The PCR process involves 3 steps which take place within apparatus thermal cycler. The three steps are:

1. Denaturation: The DNA sample is heated at 94 degree celsius. In this the double stranded DNA is converted into individual single strands.

2. Annealing: The next step involves the attachment of each single stranded DNA with a primer. This step takes place at 60 degree celsius.

3. Extension: In this under the influnece of enzyme Taq polymerase, single nucleotide bases are added to the primers. This step takes place at 72 degree celsius. Entire complentary strand build up this way by each single strand. And a new copy of double stranded DNA is produced from each single strand.