CONSTRUCTION OF A NEW STS FROM X-CHROMOSOME

It is one of those important aims in the new 5-year plan of the human genome research project([1]) to construct the STS with the resolution at 100 kb. Thus it requires about 30 000 new STS to cover the whole ge nome. In 1989, Olson([2]) first proposed the concept of STS and STS ma pping. Since then STS map has been considered to be one kind of framew ork maps for landmark. STS are single copy sequences with the lengths of several hundreds of base pairs. Their sequences are known; their po sitions are determined, and they can be specifically amplified by PCR in the presence of the total genome DNA. STS map is very special, and it is quite different from other physical maps. Restriction endonuclea se map is marked by cleavage signals, but there are too many such kind s of signals on the whole genome; Alu-PCR finger-printing map also giv es out vague results. For a single STS, it is a unique copy in the who le genome. When two YACs or Cosmids involve the same STS, they must be contiguous. The YAC contigs of the long arm of the 21st chromosome an d Y chromosome have been constructed by the STS mapping method. We onc e reported a single copy sequence library with 1 075 single copy seque nces([3]). After its sequences were confirmed to be new, its localizat ions were decided by FISH, and its appropriate PCR amplification condi tions were set up; a new STS was constructed.; Here we report an STS f rom X chromosome. and