tRNA gene copy number variation among laboratory strains of S. pombe. Normalized read depth from parallel preparations and sequencing of genomic DNA from pombe strains compared with (A) yAS99 representing the oldest laboratory strain in our laboratory derived collection (Intine et al. 2000) or (B) yFS101. The 171 tRNA gene loci are indicated along the x-axis. (A) Little variation in coverage occurs per tRNA gene among our five laboratory strains. (B) When compared with yFS101, our laboratory strains demonstrate consistent variation, showing increased read depth coverage at the loci containing the highlighted tRNA genes. For each strain, the average read depth was ∼200-fold with genome-wide uniform coverage (data not shown). The Arg(ACG), Glu(TTC), Ile(AAT), Asp(GTC), Ala(AGC), and Val(AAC) each show consistent increased read density, in some cases distributed across multiple identical loci (asterisks), which sum up to be +1×–2× average. (C) tRNA gene copy number in our laboratory strains relative to FS101 calculated from sequence read coverage in a manner different from and confirming B above, displayed for each of the 45 anticodon families in S. pombe.
