- 學位論文
水稻重組自交系連鎖圖譜之建立及遺傳重組分析
Linkage Map Construction and Genetic Recombination Analysis of a Rice Recombinant Inbred Line Population
摘要
本研究利用台中秈10號 (Taichung Sen 10, TCS10)與越光 (Koshihikari, KOSH)兩親本品種單株雜交獲得F1個體，經自交產生F2分離族群，再依單粒後裔法 (Single-Seed Descent, SSD)自交而得128個F6品系為材料，以80個SSR (Intra-SSR)分子標誌建構此重組自交系族群 (recombinant inbred line, RIL)之遺傳圖譜，12個連鎖群總長度為1475.4 cM，平均分子標誌間距為18.44 cM，為台灣首先建立之水稻RIL分子標誌連鎖圖譜，除了可做為分子標誌輔助選種材料外，亦可供遺傳重組分析之利用。 由於本研究所採用之SSR分子標誌具有共顯性，故可以SSR分子標誌探討水稻各RIL之遺傳重組情形。RIL族群之偏差分離分析結果發現80個分子標誌中，有47個基因座不符合孟德爾分離率 (31：2：31或33：31)，佔所有基因座的58.75％，且發現在第二、第六和第九對染色體極易發生偏差分離現象，而第一、第八和第十二對染色體，則偏離發生率較低。而由F1繁殖至RIL族群，每對染色體平均發生重組次數為2.37次，以第十二對平均重組次數最高 (4.19次)，第三對平均重組次數最低 (1.3次)。RIL族群之第一、第二、第三、第四、第五、第六、第八、第九、第十、第十一及第十二對染色體有較大之秈稻親本遺傳貢獻成份，唯有在第七對染色體上，稉稻親本之遺傳貢獻成份略高於秈稻。十二對染色體之平均同結合與異結合比例分別為94.6％及5.4％，偏離F6世代同結合基因型之比例理論值 (96.9％)，而分別在第六對染色體上有最大之同結合比例 (98％)，第二對染色體有最小之同結合比例 (90％)。除此之外，本研究在RIL族群中發現16個新分離之對偶基因，為兩親本均不具有之對偶基因。本研究結果顯示偏差分離在RIL族群中普遍存在，且多偏向秈稻親本之遺傳貢獻成份，並具有異結合比例略高於理論值之現象，RIL族群雖經多代自交，具有高度同結合特性，但族群內仍有部份重複序列或鄰近序列變異之發生。 本研究建立台灣第一個水稻RIL族群及其分子標誌連鎖圖譜，未來將可提供水稻重要性狀之遺傳研究及水稻雜交後代育種選拔之參考。
並列摘要
A molecular linkage map of rice was constructed using 128 recombinant inbred lines (RILs) from an inter-subspecific cross between cultivars Taichung-Sen 10 (TCS10) and Koshihikari (KOSH). It consists of 80 SSR (Intra-SSR) DNA markers distributed in 12 linkage groups, totally spanning 1475.4 cM with an average interval spacing 18.44 cM. This is the first RIL linkage map of rice in Taiwan, and it is a powerful tool for marker-assisted selection and genetic recombination studies. Since the SSR DNA markers have codominant inheritance, it makes study genetic recombination of the RIL individuals become possible. According the genotypic frequencies of SSR markers, segregation distortion was found in the RIL population. About 58.75％ of investigated markers, 47 out of 80, were segregated distortedly from Medelian ratios (31:2:31 or 33:31). Significant distortion segregation is often found in the marker loci of chromosomes 2, 6, and 9, and seldom found in the chromosomes 1, 8, and 12. The averaged recombination frequency was 2.37 times per pair of chromosomes. The chromosomes 12 and 3 respectively had the highest (4.19 times) and the lowest (1.3 times) frequencies of recombination in the RIL population. Compared to japonica type parent (Koshihikari), indica type parent (Taichung-Sen 10) contributed more genetic materials in the chromosomes 1, 2, 3, 4, 5, 6, 8, 9, 10, 11, and 12, to the RIL population, but less in the chromosome 7. The averaged homozygosity (94.6％) was deviated from the expected ratio 96.9％. The marker loci of chromosomes 6 and 2 respectively had the highest (98％) and the lowest (90％) homozygosity ratio in the RIL population. There were 16 alleles segregating in the RIL population but not detected in both parents. The sequence variations at the simple repeats or the flanking regions were detected. Our results have revealed that segregation distortion to indica genetic background and relatively high levels of heterozygosity are often found in the RIL population. This study has developed the first rice RIL population and constructed the linkage map. It is a useful tool for genetic analysis of important traits and progeny selection of cross breeding.
參考文獻
被引用紀錄
延伸閱讀
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