Nanopore sequencing enables near-complete de novo assembly of Saccharomyces cerevisiae reference strain CEN.PK113-7D.
Level 5 - mechanism / opinion, no new human data
Bench research / microbial sequencing study; Level 5 by design analogy.
PubMed 28961779 · doi:10.1093/femsyr/fox074
What was done
Researchers performed de novo whole-genome sequencing of the haploid *Saccharomyces cerevisiae* model strain CEN.PK113-7D using exclusively the Oxford Nanopore Technologies MinION platform to overcome sequence gaps and reference-scaffolding biases present in prior short-read assemblies.
What was found
The assembly resolved 15 of the 16 chromosomes, the mitochondrial genome, and the 2-μm plasmid into single contigs, with all but one chromosome starting or ending in a telomere repeat. Compared to the previous CEN.PK113-7D assembly, the new assembly added 770 Kbp of sequence containing 248 gene annotations. It also revealed a translocation between chromosomes III and VIII that caused the misidentification of a *MAL* locus in the prior assembly.
Why it matters
This provides a corrected, high-quality reference genome and functional gene set for a standard model strain in metabolic engineering and industrial biotechnology, while showing the necessity of long reads to resolve structural rearrangements without reference bias.
Limits
The study is limited to a single yeast strain. One chromosome was not fully resolved into a single contig. As reported in the abstract, specific base-accuracy metrics, read depths, and orthogonal experimental validations (such as PCR verification of the translocation) were not detailed.
Cited by
- supports Saccharomyces cerevisiae (baker's yeast) cells have 16 linear chromosomes in their haploid state, or 32 when mated and diploid.