Genetic variation in humans has been catalogued as, for example, by the International HapMap Project. A haplotype is an assemblage of some or all of the genetic variation on a chromosome. It is important to know whether two or more genetic variants (either mutations or non-deleterious polymorphisms) are present on the same or different homologous chromosomes, i.e., whether they are adjacent to one another or on opposite chromosomes. This is because they may interact depending on whether they are in cis or trans. Examples of this type of genetic interactions include: asthma, where certain drugs work better or worse depending upon the interplay of several genetic differences in the ADRB2 gene; and a common form of male sterility which is due to the interaction of two mutations in the CFTR gene. In these and similar disorders where medical treatment depends upon an individual's genetic status, haplotyping tests to obtain this information are either dependent upon population-based assumptions that may not hold for an individual, or are extremely difficult and expensive. Thus, there is need for a method to determine long-range haplotypes (those separated by thousands of nucleotides) directly. This project will expand upon preliminary studies which show that a specialized form of molecular testing can meet many of these medical needs. The overall goal of the this proposal is to develop and refine a method for identifying haplotypes spanning many kilobases that is rapid, simple, inexpensive, requires only small amounts of genomic DNA, and is easily scalable for large population studies. The prototype assay is termed LLR.
The specific aims for this program are to: 1) develop an assay to haplotype the beta-2-adrenergic receptor (ADRB2) gene using LLR; and 2) develop an assay to haplotype the cystic fibrosis transmembrane conductance regulator (CFTR) gene for deltaF508 and 5T/7T/9T mutations using LLR. This novel, technology-based project has the potential to produce major advances in clinical genetics and pharmacogenomics by providing a tool for correctly characterizing human genetic variation. A large part of health is dependent on genetics. This project will develop a new genetic test to predict who will inherit or who has certain diseases like male sterility. The new test will also be useful in determining the effectiveness of drug treatment, for example, in asthma patients because there is a genetic component to the drug response. ? ? ?
