The unknown sex life of yeast cells

Øjvind Winge at a microscope in the Carlsberg Research Laboratory. Here, his study of the yeast cell Saccharomyces cerevisiae documented its sexual reproduction and laid the foundation for modern yeast genetics. Photo: Bent Mann Nielsen Fotografi / Køge Arkiverne

A single cell can hold many of life’s mechanisms. This was discovered during the first half of the 20th century, when the yeast cell became a living laboratory for genetic research. One of the people who saw its potential was the botanist Øjvind Winge (1886–1964).

Using yeast as his model organism throughout, he blazed new trails in genetics. He helped lay the foundation for modern biotechnology and made genetic knowledge a key aspect in the science of brewing.

Explore the book 'From Yeast to Universe'

This chapter is an excerpt from the book 'From Yeast to Universe – Danish Basic Research Supported by the Carlsberg Foundation: 150 Highlights from 150 Years', published by Strandberg Publishing to mark the Carlsberg Foundation’s 150th anniversary. The book offers a kaleidoscopic insight into 150 examples of significant and memorable Danish basic research activities supported by the Carlsberg Foundation over a century and a half. The 150 examples have been selected by 25 Danish researchers.

Like many other researchers, Winge was driven by restless curiosity. As a botany student, he had amassed considerable knowledge about fungi, and much of his scientific career was dedicated to the study of fungi and genetics. Yeast, a single-celled form of fungi, became his preferred research object and served as a shortcut in his efforts to uncover the mechanisms of heredity: yeast reproduces rapidly, it can be grown in a lab, and its cells can be observed directly under a microscope – perfect conditions for the early science of genetics.

Winge’s research breakthrough happened in 1935, while he was the head of the physiological department of the Carlsberg Research Laboratory. Here he demonstrated that yeast has a sexual reproductive cycle that alternates between a haploid and a diploid phase and that it is possible to cross-breed strains and trace their heredity. At the time, the fact that a single-celled organism has a sexual cycle with co-existing genes from two ‘parents’ was a transformative discovery.

Winge’s experiments showed that after two yeast cells fuse during mating, their genetic material combines and doubles, and the resulting cell forms four spores. Through this simple but elegant mechanism, Winge could observe how individual genetic traits were shared, combined and passed on, as the life cycle of the yeast virtually revealed the internal workings of heredity, step by step. This allowed him to discover patterns and regularities that later became pillars of our understanding of genetic recombination.

At the Carlsberg Research Laboratory, Winge systematically cross-bred yeast strains, combining both natural variants and new mutants that he generated through X-ray radiation.

Grant

Grant years: 1910–1964 (first and latest) Purpose: Includes research into cellular biology, studies of genetics, and laboratory research 1933–1956 (annual support for the Carlsberg Research Laboratory)

One discovery in particular proved significant: when two different yeast strains are cross-bred, the hybrid offspring may become even stronger and more productive. This phenomenon, known as hybrid vigour, became an essential concept in targeted yeast breeding.

Winge’s work had great significance for modern fermentation industries and breweries. His genetic methods went on to enable breweries to select and cultivate specific yeast strains that would produce the perfect flavour and alcohol content.

The chapter is written by Kristian Sjøgren.