The power point presentation which we made available on line when we first started this web site was titled Genomics: A New Revolution in Science and the subtitle was: an introduction to promises…As I discussed the presentation at various conferences and conventions through last fall and winter, the new part to most teachers was the discussion of SNP’s and the promises were related to what we defined as personalized medicine. Since that time, there seems to be not a month goes by when there is not some sensational announcement in the newspaper which mentions SNP’s or personalized medicine. It was not a crystal ball which allowed me to make these predictions; it was the knowledge and confidence of scientists such as Genome Alberta’s Dr. Gijs van Rooijen giving me direction as I was preparing this curricular offering.

A standard discussion in high school biology courses centers around hemoglobin, three dimensional properties of proteins and the role of a single point mutation leading to sickle cell anemia. Some text books speculate on the role of malaria leading to the increased frequency of the sickle gene in the population as it relates to the homozygous and heterozygous individual. Biochemists have known since the late 1960’s that there were at least 9 other types of hemoglobin (phenotypes) but these do not have any apparent metabolic implications. In other words, these genetic diffences were viewed as just chance mutations. Recent work on the human genome project may help elucidate these diffences in the hemoglobin. 

One of the most interesting surprise findings of the human genome project was that approximately 93% of the genes have points where there are differences in the sequence of nucleotides. Single nucleotide polymorphisms (SNPs) were defined as points in genome where 2 or more alternative alleles are found in >1% of population. Further research discovered that 93% genes have SNPs. Of these, approximately 40% will lead to a change in an amino acid (This is an opportunity to discuss wobble hypothesis), and it was predicted that SNPs may have important consequences for health/disease. SNPs are considered to be evolutionarily stable, i.e., not changing in frequency from generation to generation (This is a real example of Hardy-Weinberg equilibrium).

The genotype of a person describes the set of alleles a person has. This includes all the persons SNP alleles. About 10 million SNPs exist. The closer together they are, the more likely they will be inherited together. This reaffirms our model of crossing over and linked genes. The SNPs in a region of the chromosome are called haplotypes

Since SNP’s may have health/disease consequences, a partnership of scientists and funding agencies from Canada, China, Japan, Nigeria, the United Kingdom and the United States was formed. Called the International HapMap Project, its purpose was to develop a public resource that will help researchers find genes associated with human disease and response to pharmaceuticals. Simply put, the goal of the International HapMap Project is to develop a haplotype map of the human genome which will describe the common patterns of human DNA sequence variation.

Through SNP’s and the HapMap project, there will be increased opportunity for what is called “Personalized” medicine. Personalized medicine makes use of molecular analysis to manage a patient’s disease by helping physicians and patients choose the disease management approaches likely to work best in the context of a patient’s genetic and environmental profile. The technology is already available in some cases to do a quick genetic test determining haplotypes, and prescribing the appropriate medicine and dose based on the individual genetic information. Under traditional medicine, medicines are prescribed based on population based evidence. There are sometime extreme side effects. Personalized medicine uses an individual’s own genetic information to predict treatments and dosages.