BS ISO 18074:2015 pdf free
BS ISO 18074:2015 pdf free.Textiles一Identification of some animal fibres by DNA analysis method一Cashmere, wool, yak and their blends
First step: Amplification is started by the PCR method. The two different primers for one animal fibre which have the different growth directions of forward and reverse are prepared. The primers act as an initiator and the substrate nucleotides are added selectively on the strands bases so as to make a copy.The length of the DNA fragment is not determined on this step yet.
Before the second step, DNA is heated and again the double helical strand becomes two single DNA strands. There are two lengths of single strand DNA which is a long DNA originated from animal fibre and the middle length DNA with one starting point by initiators.
Second step: Two kinds of amplification occur in this step: 1) amplification of the first step; and 2) another amplification. Then another amplification takes place on the short DNA fragment obtained from the first step amplification. At this point, the length is not determined yet, but it has the initiated point by the forward primer or reversed primer. For this DNA fragment, the amplification started by the primers with the opposite directions is terminated at the starting position of the first step.
So, amplified DNAS are heated again and the double helical strands become two single DNA strands.There are 3 kinds of the single strand DNA which is a long DNA originated from animal fibre and the middle length DNA with one starting point by initiators and the short length DNA with both ends created by the primers as a starting point of amplification.
Third step: Amplification of the first and second steps continues. Amplification of the short length DNA with both ends created by the primers begins, creating a copy with the same short length.BS ISO 18074 pdf free download.
