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Gettle, N.

Publications and source records attributed to Gettle, N..

2 recordsLinked to original sources

Harnessing the power of technical and natural variation in 116 yeast datasets to benchmark long read assembly pipelines

With increases in throughput and reductions in cost, long read sequencing has become the standard for most genome assembly projects and has opened up new avenues for large-scale genomic research. While more amenable to assembly than short-read sequence data, long-read datasets tend to have higher error rates. To address this problem numerous tools have been developed to correct reads before assembly and polish assembled contigs. Although, numerous studies have been conducted to assess or benchmark these tools, few capture the real variance in long read sequence data that might affect tool performance much less full pipeline performance. To address these shortcomings, we compiled a dataset containing long-read sequences of 116 different strains of brewers yeast, S. cerevisiae, gathered largely from public databases and evaluated different assembly-related tools as well as their interactions. We found that pre-assembly short-read error correction of long reads combined with post-assembly short-read polishing provided the best assemblies. We also found that correction/polishing steps with uncorrected long reads often lead to degradation of assembly quality. Finally, we show which tools and pipelines work best with different types of input data.

bioinformatics↗

Tracking the origin of Baker's yeast: Seven new long-read genomes of highly divergent, wild Saccharomyces cerevisiae strains from East Asia

Comparative genome analyses have suggested East Asia to be the cradle of the domesticated microbe Brewers yeast (Saccharomyces cerevisiae), used in the food and biotechnology industry worldwide. Here, we provide seven new, high quality long read genomes of non-domesticated yeast strains isolated from primeval forests and other natural environments in China and Taiwan. In a comprehensive analysis of our new genome assemblies, along with other long read Saccharomycetes genomes available, we show that the newly sequenced East Asian strains are among the closest living relatives of the ancestors of the global diversity of Brewers yeast, confirming predictions made from short read genomic data. Three of these strains (termed the East Asian Clade IX Complex here) share a recent ancestry and evolutionary history suggesting an early divergence from other S. cerevisiae strains before the larger radiation of the species, and prior to its domestication. Our genomic analyses reveal that the wild East Asian strains contain elevated levels of structural variations. The new genomic resources provided here contribute to our understanding of the natural diversity of S. cerevisiae, expand the intraspecific genetic variation found in this this heavily domesticated microbe, and provide a foundation for understanding its origin and global colonization history. Significance statementBrewers yeast (Saccharomyces cerevisiae) is a domesticated microbe and research model organism with a global distribution, and suspected origin in East Asia. So far only limited genomic resources are available from non-domesticated lineages. This study provides seven new, high quality long read genomes of strains isolated from primeval forests and other natural environments in China and Taiwan. Comparative genomics reveal elevated levels of structural variation in this group, and early phylogenetic branching prior to the global radiation of the species. These new genomic resources expand our understanding of the evolutionary history of Brewers yeast, and illustrate what the ancestors of this highly successful microbe may have looked like.

genomics↗