| Summary: | 碩士 === 國立臺灣大學 === 植物學研究所 === 86 === Amplified restriction fragment polymorphism (AFLP) is a PCR-based DNA fingerprinting technique. The technique involves three steps (I) restriction of the DNA and ligation of oligonucleotide adapters, (II) selective amplification of sets of restriction fragments and (III) analysis of the amplified fragments on denaturing polyacrylamind gels. PCR amplification of restriction fragments is achieved by using the adapter and restriction site sequence as target sites for primer annealing. The selective amplification is achieved by the use of primers that extend into the restriction fragments, amplifying only those fragments in which the primer extensions match the nucleotides flanking the restriction sites. This method, sets of restriction fragments may be visualized by PCR without knowledge of nucleotide sequence.
To investigate the genetic diverification of oncidium by use of AFLP markets, 56 primer combinations were applied to generate AFLP patterns with eight oncidium lines, e.g. Gold1. Gold2. Gower Ramsey. Golden Star. Hamana, Shonan, Volcano Queen and Yellow King respectively.
With seven primer combinations, the generated AFLP fingerprintings are hard to detect the polymorphism from eight lines. With the remaining 47 primer combinations, on average about 138 amplification products were generated and the polymorphism rate between the eight lines was generally over 60%.
At present study, AFLP markers were successfully employed to detect genetic differentiation among eight oncidium lines. Nei & Li coefficient of genetic similarity was used to partition the total genetic variation in between. From the genetic distance cluster map, we can find that the distance between eight lines is 18~36%. The lines can be differentiated into two groups: (I) Gold 1. Gold 2. Gower Ramsey. Hamana. Shonan and Volcaon Queen (II) Gold Star and Yellow King. The results are coincident to phenotypic variation. In conclusion the AFLP technique is an adequate and powerful tool to evaluate genetic diversification.
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