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草棉基于荧光原位杂交(FISH)的核型公式为2n=2x=26=16m+10sm(6sat),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rD-NA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。
The karyotype formula of cottonseed based on fluorescence in situ hybridization (FISH) was 2n = 2x = 26 = 16m + 10sm (6sat), the relative lengths of short and long arms were 1.43-4.14 and 3.34-5.18, respectively. The chromosome length ratio The ratio of the longest to the shortest chromosome) was 1.63. Chromosome group has 6 satellite, are located in the last three chromosomes of the short arm, which is located on the 12th and 13th chromosomes in the DAPI and rhodamine images clearly visible, but located on chromosome 11 Body is not observed in DAPI images. Six (3 pairs) of NOR signals were detected, with the satellite isomerism, one for the telomeres on the chromosome and two for the next. GISH-NOR was detected on chromosome of soma by Raymond cotton genomic DNA (gDNA) probe. The number, location and size of GISH-NOR were the same as that of 45S probe, indicating that the karyotype of FISH is higher than that of conventional karyotype Non-FISH karyotype) is more accurate. In combination with other FISH data in this laboratory, it has been deduced that some tandem repeats, such as rDNA, may have undergone major changes, including amplification, translocation or deletion, etc., in the A genome cotton species as allotetraploid cotton species as donors . One possible explanation for the D genome-specific GISH-NOR is that there are far more rDNA copies of D genome cotton than A genome cotton. NOR or GISH-NOR sites and other aspects of further research, help to explore the rD-NA gene evolution and function, and as a marker applied to cotton genomic mapping of chromosome number.