Fitness in fungi

Fitness is the relative contribution of one genotype, relative to that of another. But how does one measure and quantify this? In fungi, a variety of measures (“fitness proxies”) are used. Growth rate of the mycelium is a popular one, because it can repeatedly and consistently be measured; but does it reflect fitness? In some species under laboratory circumstances it probably does, such as in for example in Aspergillus. In the lab, the growth rate of the mycelium reflects the spore production which is linearly correlated (Gifford & Schoustra 2013). But can this be generalized? 

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Pombe is a hybrid

Preprint on biorxiv.org

We just posted a preprint of our manuscript on bioRxiv. In the paper we analyzed the sequencing data from 161 different fission yeast strains and showed that these are a recent hybrids between (at least) two populations that diverged from each other about 2300 years ago, and about 20 outcrossing generations (probably sometime in the last 500 years) started to hybridize. The genomes still have large haplotype blocks from the two different populations. Long-read sequencing methods (PacBio’s SMRT and and NanoPore’s MinIon) showed some small structural variants and a few large structural variation, but these variants are present only at low frequencies and do not explain the haplotype blocks.

Tusso, Sergio, Bart P.S. Nieuwenhuis, Fritz J. Sedlazeck, John W. Davey, Daniel Jeffares, and Jochen B. W. Wolf. “Ancestral Admixture and Structural Mutation Define Global Biodiversity in Fission Yeast.” BioRxiv, September 12, 2018. https://doi.org/10.1101/415091.
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