Sasha Levy, an Assistant Professor of Physical and Quantitative Biology at Stony Brook University, and Jamie Blundell Ph.D found a way to track the changes in cell lineages, a project that could lead to a greater understanding of how diseases evolve over time. Photo by Stony Brook University Newsroom
By Catherine Bonke
What if you could track every family lineage throughout thousands of years of history to see the rise of great leaders and empires or dictators and wars? Taking that a step further, what if you could take a population of asexual body cells and and track their lineage to see the rise of a tumor or a disease in a matter of days or weeks?
This is how Sasha Levy, an evolutionary biologist and professor of biochemistry and cell biology at Stony Brook University, explained the basic idea his newest findings, published in his research paper “Quantitative evolutionary dynamics using high resolution lineage tracking.”
Levy’s research looked at Saccharomyces cerevisiae, a form of yeast that is not only ideal for scientific study because of it’s high reproductive rate, but also is very similar to the kinds of harmful yeast, bacteria and parasites that can harm humans. By using DNA sequencing that was processed through a computer chip, Levy and his research team were able to track the individual lineages of the reproducing cells, which allowed him to closely look at mutations and exactly when they showed up in the genome.
“Evolution works by mass action,” Levy said. Rather than one adaptive mutation sweeping through an entire population of cells, there are multitudes of small mutations that occur within different lineages, or families, in the population of cells. “Thousands or tens or thousands of lineages are getting adaptive mutations all the time and they’re fighting it out.”
Putting a magnifying glass on each individual change within a population of cells can help scientists and doctors understand which mutations are noteworthy and how those mutations help bacteria become resistance to vaccines and other drugs.
It can also show how cancer cells become tumors that metastasize, or spread throughout the body.
“The state of the art now is to have a tumor, it grows really big and then you take the current days census of what’s happening,” Levy said, further explaining the possible clinical applications for his research. “We’re hoping to watch cancer develop and by watching it develop on a granular scale we can understand which mutations are important and which are not important.”
Going back to his family lineage analogy, Levy said, “We take census of how many last names there are in a population and then we do it over time and ask how many times a name shows up.”
Levy and his team track the changes in the different lineages through DNA sequencing that is processed through a computer chip. It’s a aspect of biological research that is growing exponentially, with a similar speed as computer processing. They take a group of 26 nucleotides, and put it into a specific area of the genome and then amplify that specific part, to take a closer look at the sequence.
Levy’s started the research with his colleague Jamie Blundell when the two were post-doc students at Stanford. They both traveled to the Stony Brook University Louis and Beatrice Laufer Center to continue the work. The paper was published in Nature in February of this year.