MAPPING HUMAN CHROMOSOME 11

一个完整的人类染色体图谱将极大地促进

A complete map for all human chromosomes would greatly facilitate understanding human biology and molecular disease. The studies proposed here will generate a restriction map of human chromosome 11 and align this map with the cytogenetic and genetic maps. Chromosome 11 was chosen since it encodes genes and has regions associated with diseases resulting from structural defects involved with oncogenes, growth factors, metabolic disorders, abnormal development, tumors, leukemias, chromosomal rearrangements and fragile sites. Another important reason for this study is the large number of cloned probes that have been mapped to this chromosome. It is clear that a very large number of ordered genetic markers are essential for accomplishing a complete map. Rather than employ only random DNA probes, we will isolate a unique set of ordered DNA clones for human chromosome 11 which are located at recognition sites for the rare cutting restriction enzymes NotI and SfiI. It is estimated that about 300 clones containing these recognition sites on chromosome 11 will be obtained, and will be sufficient to generate a complete chromosome 11 restriction map composed of overlapping DNA fragments 0.5 to 3 million base pairs in size. Probes will be isolated from a library of a Chinese hamster-human cell hybrid that retains chromosome 11 as its only chromosome. Positive human probes will be screened for the presence of rare cutter sites using labeled oligonucleotides for NotI and SfiI sequences. These sequences will be localized on chromosome 11 using our rapid mapping cell hybrid panel that will divide this chromosome into about tow dozen regions. Using pulsed field gel electrophoresis and these ordered markers, we will generate a restriction map for chromosome 11. The 140 random DNA markers that we have already mapped to regions of chromosome 11 and the more than 50 random probes we are currently isolating will be used to fill in and complete an ordered restriction map. Those probes recognizing restriction fragment polymorphisms will be employed in linkage maps to align the physical and genetic maps. Genes and abnormal chromosomal breakpoints associated with disease will be located on large restriction fragments which will precisely assign them on the physical map. This information will be significant for the molecular characterization of disease.