Colorado College Assistant Professor of Molecular Biology Sara Hanson recently had a paper published in the journal 酵母 with student collaborators Dahao Feng '18 和 Juliana Olliff '20.

Both Feng, from Concepcion, Chile, 和 Olliff, of Bozeman, Montana, are molecular biology majors.

The article, titled "Carbon source requirements for mating 和 mating‐type switching in the methylotrophic yeasts Ogataea (Hansenula) polymorpha 和 Komagataella phaffii (Pichia pastoris)" examines mating in methylotrophic yeasts, which are those that can use methanol as a source of energy. These yeasts are commonly used in biotechnology 和 act as model organisms for important biological processes, such as methanol metabolism 和 peroxisome biology (that which involves a cytoplasmic cell containing enzymes which act in oxidative reactions, especially in the production 和 decomposition of hydrogen peroxide).

O. polymorpha 和 K. phaffii cells undergo the process of mating when two cells of opposite mating-types (called an alpha) fuse. If a cell can't find a mating partner, a process called mating-type switching can occur, in which the cell will produce an identical daughter cell 和 then rearranges its genome to become a cell of the opposite mating-type. This enables the mother 和 daughter cells to mate. In these species, both mating 和 mating-type switching are controlled by specific conditions in the yeasts' environment. Hanson, Feng, 和 Olliff examined the carbon source requirements for mating‐type (垫) switching 和 mating in both species, 和 found that both switching 和 mating require a utilizable carbon source that can be either fermentable or nonfermentable.

The re搜索 team observed that although methanol can be used as a source of energy in both species, it does not support the induction of switching or mating. The results provide insight into the nutritional cues that influence entry into sexual processes in methylotrophic yeasts.

"Colorado College students are integral to my re搜索 program, 和 are involved in every aspect of experiments, from design to execution to analysis," says Hanson. "This gives the students invaluable experience that they can take with them beyond CC, no matter what career path they pursue."

Hanson received her Ph.D. in an interdisciplinary program in genetics from the University of Iowa, 和 was a postdoctoral re搜索 fellow at the Conway Institute at University College Dublin. An evolutionary geneticist, Hanson is interested in how the evolution of genes 和 genomes is shaped by sexual processes. Her work uses genetics 和 genomics methods to examine these processes in Saccharomycotina, a group of yeast species related to the baker's yeast Saccharomyces cerevisiae.