利用螢光原位雜交定位縐葉菸草的酵母菌人工染色體選殖株

Abstract

本研究以20個縐葉菸草酵母菌人工染色體(YAC)選殖株為探針，利用螢光原位雜交(FISH)將其定位在縐葉菸草的染色體上。其中17個選殖株產生的訊號散佈在核仁形成區以外的染色體各處；剩下三個選殖株在加入(B172)與不加入(B11432和B11438) Cot-1 DNA的雜交情況下，都在第一對染色體上出現一對專一的訊號。南方氏雜交的結果進一步說明B11432和B11438所攜帶的是一長段單一拷貝序列，然而B172和其他17個未被定位的選殖株則分別帶有不同份量的重複性序列。另外由於B172的一個YAC末端序列已被定位在縐葉菸草遺傳圖譜的第一連鎖群中，第一連鎖群應該屬於第一對染色體。

Chromosome locations of 20 Nicotiana plumbaginifolia genomic sequences cloned into a yeast artificial chromosome (YAC) were investigated by fluorescence in situ hybridization (FISH). Of these, 17 produced hybridization signals distributed allover the N. plubaginifolia genome except nucleolar organizing regions, while the remaining three generated one pair of signals on chromosome 1 in the presence (clone B172) or absence (clone B11432 and B11438) of Cot-1 DNA. These results, together with those from Southern analysis, suggest that the YAC clones employed in this study contain different amount of repetitive sequences. The sequence of one end of clone B172 was previously assigned to linkage group I. FISH using B172 as a probe indicates that linkage group I belongs to chromosome 1.