Genomics

A gene is a region of DNA that contains the plans to instruct cellular machinery how to make a specific protein. All proteins are encoded by genes. Hence, genes are the individual instruction sets that dictate the make-up of components that drive most cell processes.  Genetic changes can be heritable or can develop by de novo genetic mutation, and can reflect natural variability (i.e., we are 99.5% identical to each other but that 0.5% difference is sufficient to account for all of our personality and distinctions), or mutations can occur due to environmental stresses such as chemicals or radiation. 

The consequences of these changes are then reflected in the functions of proteins, which, in turn, regulate our cellular processes and our risk of illness.

A chromosome is the primary level of organization of DNA. Each human cell has 23 pairs of chromosomes (half from each parent) that vary in size. Regions of the chromosome that are not genes are known as non-coding regions.

A genotype describes an individual’s unique genetic makeup, whereas a phenotype describes an individual’s physical traits or appearances, such as blue eyes or blonde hair, which is a reflection of the genes that underlie the individual moulded by their environmental exposures and experiences.

Genomics, the basis for much disease research today, is the study of the entire repertoire of genes and the effect specific variations in these may have on various pathways of development, as well as our health and risk of illness. Over the past decade, genomics has enabled new tools for disease testing and screening. Genetic testing, which involves the screening of DNA, RNA, or proteins, is becoming increasingly common for use in detecting complex illnesses, and for non-clinical purposes such as parental testing and forensics.

Personalized medicine involves combining genetic/genomic clues with clinical information to make accurate predictions about a person’s risk for disease, the course of disease, and response to treatment in each individual.  Personalized medicine has the potential to reshape medical care: access to each individual’s genomic data will help physicians make more informed medical decisions, possibly intervene earlier in the course of a patient’s illness, and tailor therapies to a patient’s unique genetic ‘signature.’  (For more information, you can also read the related backgrounder on personalized medicine.)

 Meet the Experts:

Dr. Katherine Siminovitch identified three new genes that increase risk for a debilitating liver disease called primary biliary cirrhosis (PBC). As well, her recent research in rheumatoid arthritis (RA) is pinpointing the genetic pathways that confer risk for RA and other autoimmune disorders, so that physicians can ultimately diagnose patients earlier, and prescribe more effective, personalized therapies.

Dr. Steven Gallinger and his team are working to identify the gene(s) that may help create a ‘road map’ for familial pancreatic cancer.

Dr. Mark Silverberg is leading exciting research to discover genetic markers associated with ulcerative colitis and childhood-onset inflammatory bowel disease (IBD).

Dr. Sabine Cordes is studying the genes involved in psychiatric conditions such as depression, bipolar disorder, schizophrenia, autism and phobic disorders, since clinical and family studies have indicated there is a strong genetic component to these illnesses. She is also working on the development of simple blood tests that would accurately diagnose psychiatric disorders.