Construction and characterization of a partial bacterial artificial chromosome (BAC) library and the use of BACs for physical mapping in plants using fluorescent in situ hybridization (FISH)

A partial cotton bacterial artificial chromosome (BAC) library consisting of 1,824 clones with an average insert size of 75 kb was constructed to aid in map-based cloning and physical mapping. BAC clones were screened with both chloroplast and Gossypium hirsutum (L.) total genomic DNA and results indicate this library contains less than 3% cloned chloroplast DNA sequences and approximately 19% of the clones contain unique DNA sequences. Large unique BACs were used for fiuorescent in situ hybridization (FISH) in several Gossypium species demonstrating that BACs can be used effectively for physical mapping. Some BACs however, were shown to consist largely of unique sequences with some repetitive DNA sequences interspersed within. These clones were still useful for FISH mapping although hybridization of repetitive DNA sequences needed to be suppressed. A technique to isolate C...