The baker's yeast Saccharomyces cerevisiae has been associated with human activities for thousands of years, being the primary biological agent in baking, brewing, winemaking and other fermentation processes.
It is also one of the most important model organisms in molecular biology and genetics research. For a long time, the history and evolution of this important yeast has been a completely mystery, but recent advances in genome sequencing technologies now allow it to be studied in great detail.
Using next-generation sequencing, corresponding author Gianni Liti et. al. provide a detailed characterization of the genetic variation present within the baker's yeast species. They sequenced the genomes of 42 strains of S. cerevisiae and its closest relative S. paradoxus, which is an entirely wild species that has not had any contact with humans.
A central finding of this study is that even though strains in S. paradoxus are separated by much greater genetic distances in terms of single-nucleotide polymorphisms (SNPs), the S. cerevisiae strain genomes harbor more variation in terms of absence and presence and copy number of genes.
It has previously been observed that trait variation is also much larger in S. cerevisiae than in its wild relative. These new results therefore raise the intriguing hypothesis that this variation in the content of the genome, rather than single-nucleotide differences, underlies the large phenotypic variation in S. cerevisiae.
The authors find that the subtelomeric regions of the genomes, located just before the telomeres at each chromosome end, are highly enriched for genome variation that is likely to contribute to differences in traits between strains. This includes loss-of-function mutations that likely disrupt the function of whole genes. As an example of functional variation they describe how differences in the copy number of a subtelomeric gene cluster controls the ability of strains to grow under arsenic stress, and demonstrate that this variation is the product of convergent evolution in yeast lineages in different parts of the world.
"These genome sequences allowed us to expose surprising differences between the evolutionary histories of the common baker's yeast and its wild relative. Our results suggest that the very large diversity in traits observed between strains of baker's yeast might mostly be due to the presence or absence of entire genes rather than differences in single DNA letters."
The study provides intriguing insights into the recent history of this important organism and the relationship between genome variation and trait variation. Future research will further elucidate what role humans have played in shaping the evolution of baker's yeast, for example the extent to which the genomic variation is a consequence of yeast strains moving into novel habitats and niches opened up by human activities.
Joe Caspermeyer | EurekAlert!
How to become a T follicular helper cell
31.07.2015 | La Jolla Institute for Allergy and Immunology
Heating and cooling with light leads to ultrafast DNA diagnostics
31.07.2015 | University of California - Berkeley
Using ultracold atoms trapped in light crystals, scientists from the MPQ, LMU, and the Weizmann Institute observe a novel state of matter that never thermalizes.
What happens if one mixes cold and hot water? After some initial dynamics, one is left with lukewarm water—the system has thermalized to a new thermal...
Physicists from Regensburg and Marburg, Germany have succeeded in taking a slow-motion movie of speeding electrons in a solid driven by a strong light wave. In the process, they have unraveled a novel quantum phenomenon, which will be reported in the forthcoming edition of Nature.
The advent of ever faster electronics featuring clock rates up to the multiple-gigahertz range has revolutionized our day-to-day life. Researchers and...
Researchers have developed an ultrafast light-emitting device that can flip on and off 90 billion times a second and could form the basis of optical computing.
Joint BioEnergy Institute study identifies bacterial protein that is key to protecting rice against bacterial blight
A bacterial signal that when recognized by rice plants enables the plants to resist a devastating blight disease has been identified by a multi-national team...
Researchers in the Cockrell School of Engineering at The University of Texas at Austin are one step closer to delivering smart windows with a new level of energy efficiency, engineering materials that allow windows to reveal light without transferring heat and, conversely, to block light while allowing heat transmission, as described in two new research papers.
By allowing indoor occupants to more precisely control the energy and sunlight passing through a window, the new materials could significantly reduce costs for...
23.07.2015 | Event News
10.07.2015 | Event News
25.06.2015 | Event News
31.07.2015 | Trade Fair News
31.07.2015 | Transportation and Logistics
31.07.2015 | Physics and Astronomy