花生的荧光显带和rDNA荧光原位杂交核型分析

建立花生准确而详细的核型对于阐明其起源和开展其基因组研究十分重要。本研究采用DAPI显带和5S、45S rDNA探针双色荧光原位杂交对花生有丝分裂中期染色体进行了分析。结果表明，花生的单倍基因组总长度为(81.06±3.74) μm，最长染色体为(4.72±0.15) μm，最短染色体为(2.62±0.14)μm；有15对染色体显示了着丝粒区DAPI⁺带，其中10对为强带，5对为弱带；有2对5S rDNA位点和5对45S rDNA位点，其中1对5S与1对45S位点同线。综合染色体测量数据、DAPI⁺带和rDNA杂交信号，对花生染色体进行了准确配对和排列，建立了详细的分子细胞遗传学核型。花生的核型公式为2n=4x=40=38m+2sm(SAT)，核型不对称类型属于2A型。

Karyotype Analysis of Arachis hypogaea L. Using Fluorescence Banding and Fluorescence in situ Hybridization with rDNA Probes

The establishment of an exact and detailed karyotype of Arachis hypogaea L. was fundamental for clarification of the origin and research of the genome of the species. In this study, the mitotic metaphase chromosomes of the species were analyzed using DAPI banding and double fluorescence in situ hybridization (FISH) with 5S and 45S rDNA probes. The mean haploid karyo-type length was (81.06±3.74) μm, the longest chromosome pair was (4.72±0.15) μm and the shortest chromosome pair was (2.62±0.14) μm. In the complements of the species, fifteen pairs of the chromosomes displayed centromeric DAPI+ bands including ten pairs of strong bands and five pairs of weak bands; and two pairs of 5S and five pairs of 45S rDNA sites were showed, with one 5S site being syntenic to a 45S site. Combining the chromosome measurements with DAPI+ bands and rDNA FISH signals, the chromosomes were exactly paired and arranged, and a detailed molecular cytogenetic karyotype of A. hypogaea is established. The karyotype formula of A. hypogaea was 2n=4x=40=38m+2sm (SAT) and the asymmetric karyotype belonged to 2A type.