Highly Repetitive Tandem Arrays of a Short 32 bp Unit in thePharbitis nilGenome: theRsaIFamily

摘要

A highly repetitive DNA sequence ofPharbitis nil, designated theRsaI family, was cloned, sequenced and analyzed with respect to its genomic organization. TheRsaI family is arranged in tandem arrays and composed of a 32 bp repeat unit, which is the shortest unit thus far reported for plant repetitive sequences. TheRsaI family represents 3%of the total genomic DNA and the copy number of the 32 bp unit is estimated to be about 1×106per haploid genome. We suggest the existence of a higher order repeat unit, which may be composed of hundreds of the 32 bp units and be repeated many times in the genome