| Summary: | 碩士 === 國立屏東科技大學 === 生物科技研究所 === 96 === The Contents of Abstract in This Thesis:
Ribosome-inactivating proteins (RIP) can inhibit protein synthesis and protect plants against pathogens. Molecular variations of the RIP gene family, however, are still unclear. In this study, we estimate the nucleotide variations and construct the pattern of molecular evolution in RIP gene family using bitter melon as a model plant. We identify the genetic diversity and molecular evolutionary history within and among wild, hybrid, and cultivated varieties of bitter melons. Samples were analyzed using PCR and cloning to sequence three different loci of the RIP genes (locus 1-3) and one neutral chloroplast spacer. We analysis 72 sequences in each locus of RIP genes; 34 haplotypes in locus 1, 37 haplotypes in locus 2, and 40 hyplotypes in locus 3 were identified. In each type of RIP genes, the numbers of nonsynonymous mutations are more than synonymous mutations. Nucleotide diversity and divergence were detected 0.01006 (θ) and 0.00321 (π) in locus 1, 0.01421 and 0.00373 in locus 2, and 0.01406 and 0.00412 in locus 3. Test of selection and neutrality (Tajima’s D) were performed to assess the evolutionary processes influencing each gene region and indicated significant values in locus 1 (D = -2.299, p<0.01), locus 2 (D = -2.416, p<0.01) and locus 3 (D = -2.367, p<0.01), but neutral in the chloroplast DNA atpB-rbcL spacer. The minimum recombination event in each type of RIP genes has detected once between wild, hybrid, and cultivated varieties. Significant values in neutral test and ratio between nonsynonymous and synonymous mutations can be indicative the Ribosome-inactivating proteins gene family can be affected by selective sweep and domesticate force.
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