Model systems are used extensively by scientists to answer a myriad of questions related to subjects ranging from development to complex diseases. The use of model systems (such as yeast, flies, worms, and mice) as tools for fundamental research did not happen in a single day. It takes several years of experimental dissection to develop and establish a model system. However, many of us still strive to understand the suitability of a specific system to answer a specific question. Let’s say you want to do a drug screen for a specific disease. Should you choose a fly or a worm model? Is the genetic sequence of your gene of interest conserved from mice to humans? Is that gene expressed in yeast? What tools should you use? The advantage of one model may be a disadvantage for the other. Thus, the limiting factor for choosing a model is the question being asked.

Mark McCormick, PhD.

Mark McCormick, PhD.

To answer these questions and to explore outside our ‘comfort zones’, the Post Doctoral Association (PDA) at The Buck Institute has started a seminar series on model organism systems. The inaugural seminar was held on October 28th, 2014, and featured Mark McCormick, PhD, a post-doctoral research fellow from Prof. Brian Kennedy’s lab. Mark completed his PhD at the University of California, San Francisco in the lab of Cynthia Kenyon. Presently, he specializes in using Saccharomyces cerevisiae (yeast) to understand the basic biology of aging.

Mark’s talk focused on understanding the fundamental mechanisms of aging using yeast as a model system. He began by laying a foundation of life expectancy for various diseases giving a statistical meaning and significance to the study of aging. He introduced the audience to the distinction between chronological and replicative life span, and how well molecular signaling pathways in yeast are conserved amongst other model systems across the phyla.

Budding yeast (species Saccharomyces cerevisiae) shown under a microscope.

Saccharomyces cerevisiae yeast cells visualized through a microscope.

Some of the challenges of a model system may be the generation of viable genetic mutants. Mark discussed the tools and techniques for generating single and double mutants in yeast and also emphasized the ease of making such mutants. He also highlighted the Yeast GFP-tagged open reading frame (ORF) clone collection and its usefulness for understanding complex regulatory networks and protein-protein interactions.. Lastly, the audience was informed about the available yeast genomic databases as well as ongoing research in the field of yeast biology and how both can be combined to answer complex questions of aging.

Overall, the talk was very lucid and well appreciated by all as was evident from a number of interesting questions from the audience.