CAJ | 학술논문

草棉基于荧光原位杂交(FISH)的核型公式为2n = 2x = 26 = 16m + 10sm (6 sat),短臂和长臂的相对长度分别为1.43～4.14和3.34～5.18,染色体长度比(最长与最短染色体的比值)是1.63.染色体组有6个随体,都定位在最后3条染色体的短臂上,其中位于第12和第13号染色体的随体在DAPI和罗丹明镜像中明显可见,但位于第11号染色体的随体在DAPI镜像中观察不到.检测到6个(3对)NOR信号,与随体同位,1对位于染色体端粒,2对紧接着丝粒.雷蒙德氏棉基因组DNA(gDNA)作探针时,在体细胞染色体上检测到GISH-NOR,其数量、位置和大小与45S探针的NOR相同,说明FISH核型比以前常规核型(非FISH核型)更精确.结合本试验室其它FISH资料,推断A基因组棉种在作为供体形成异源四倍体棉种以来,一些串连重复序列如rDNA可能发生了很大变化,包括扩增、易位或缺失等.对于D基因组特有的GISH-NOR的一个可能解释,就是D基因组棉种的rDNA拷贝数远远多于A基因组棉种.NOR或者GISH-NOR位点等方面的进一步研究,有助于探讨rDNA基因进化和功能,并作为一种标记应用于棉属构建染色体序号定位的物理图谱.
초면기우형광원위잡교(FISH)적핵형공식위2n = 2x = 26 = 16m + 10sm (6 sat),단비화장비적상대장도분별위1.43～4.14화3.34～5.18,염색체장도비(최장여최단염색체적비치)시1.63.염색체조유6개수체,도정위재최후3조염색체적단비상,기중위우제12화제13호염색체적수체재DAPI화라단명경상중명현가견,단위우제11호염색체적수체재DAPI경상중관찰불도.검측도6개(3대)NOR신호,여수체동위,1대위우염색체단립,2대긴접착사립.뢰몽덕씨면기인조DNA(gDNA)작탐침시,재체세포염색체상검측도GISH-NOR,기수량、위치화대소여45S탐침적NOR상동,설명FISH핵형비이전상규핵형(비FISH핵형)경정학.결합본시험실기타FISH자료,추단A기인조면충재작위공체형성이원사배체면충이래,일사천련중복서렬여rDNA가능발생료흔대변화,포괄확증、역위혹결실등.대우D기인조특유적GISH-NOR적일개가능해석,취시D기인조면충적rDNA고패수원원다우A기인조면충.NOR혹자GISH-NOR위점등방면적진일보연구,유조우탐토rDNA기인진화화공능,병작위일충표기응용우면속구건염색체서호정위적물리도보.
The formula for FISH-based karyotype of Gossypium herbaceum was as 2n = 2x = 26 = 16 m + 10 sm (6 sat), with the range in relative length of short and long arms from 1.43 to 4.14, 3.34 to 5.18, respectively. The ratio between the largest chromosomes and the smallest one was 1.63. Six satellite loci were mapped on short arms of the last three chromosomes. The satellites on chromosomes 12 and 13 were clearly visable in both DAPI and rhodamine/DAPI images, however the satellite on chromosome 11 was not detected in DAPI images.Six, in three pairs, of NORs were observed adjacent to the satellite sites, with one pair on telomere and two pairs near centromeres. When gDNA from G. raimondii was used as probe, GISH-NORs were scored in mitotic chromosomes of G. herbaceum with the same numbers, locations and sizes as 45S rDNA NORs. It could be therefore concluded that FISH-based karyotype analyses were more detailed than previous karyotype (non-FISH). Based on this study in conjunction with our other FISH results, there might be great amplifications or pericentric inversions of rDNA in modern A genome species after its contribution to allotetraploid originations, or deamplifications/deletions of tandem repeats like rDNA in extant allotetraploids following their polyploidization. An explanation to D genome specific GISH-NORs is that rDNA contents in D genome species may be much more than those in A genome species. The NORs or GISH-NORs herein may facilitate future locus-specific studies on rRNA gene evolution and function, and also may be useful in developing physical map specific to chromosome order in Gossypium.