Microdissection of a single chromosome and construction of the microclone library from soybean

Abstract

A single chromosome was microdissected from the metaphase chromosomes of soybean by using a glass needle. After two rounds of Sau3A linker-adaptor-mediated PCR, smear DNA fragments ranged from 0.3–2.5 kb were obtained. Southern hybridization showed that the PCR products from the dissected chromosome were homologous with the soybean genomic DNA. In situ hybridization of the chromosome PCR products to the mitotic metaphase spreads showed that the PCR products were hybridized to the soybean, but the chromosomal signals were not restricted to the microdissected chromosome. The second-round PCR products from the microdissected chromosome were cloned into plasmid vector to generate a chromosome-specific microclone library, which included approximately 200,000 recombinant clones. 178 randomly selected clones were estimated to range in size from 0.3∼1.8 kb, with an average size of 830 bp, of which approximately 44% were high/medium copy clones, while 56% were low/unique copy clones.