| 摘要: | 摘要
甘藷是世界最重要的糧食作物之一，雖然甘藷已被人類栽植超過5000年，它們的馴化機制仍有待釐清。由於經馴化之物種會受到選汰壓力的作用，因此使用SSR之Ipomoea的EST序列為分子標記，利用GENEPOP等軟體來分析89個甘藷品種在馴化過程(domestication)中是否有基因座受到選汰壓力。結果顯示基因座之分子標記的多型性比例約為97.4%，而栽培種之基因歧異度較野生種高。各遺傳分群檢測與PCoA的結果大致相符合。不同中性檢驗的偵測結果，皆指出栽培過程有受馴化的現象，且5個基因座為受選汰的基因座，並達到顯著性差異。受選汰基因功能屬於一次代謝相關的功能，如調控基因表現，此與多數穀類作物的馴化研究相似，或許這是受栽培作物普遍存在的共同機制。
Abstract
Ipomoea batatas (sweet potato) is one of the most important corps in the world. Although cultivated sweet potatoes have been domesticated for more than 5,000 years, their domestication mechanisms remain unclear. To investigate whether 89 different cultivated sweet potatoes have experienced selected stresses during domestication, simple sequence repeats (SSRs) derived from expressed sequence tags (ESTs) were genotyped. Genetic structural analyses in PCoA indicated two separated groups, i.e. wild species and sweet potatoes, consisting with the result of other analyses. Analyses reveal that the polymorphism of sampled loci is about 97.4%. In addition, gene diversity appears much higher in cultivated sweet potatoes than in wild species. We detected five selected loci by different analyses. Our results suggest that domesticated species have experienced selected stresses. Selected loci are related to primary metabolism such as gene expression and photosynthesis. Because selected genes of primary metabolites have been found in cereal crops, combining with our findings in the sweet potatoes, a non-cereal crop, we propose that selection of primary metabolism genes might be common in domestication of crops. |
