canavanine-resistant mutants
We performed whole genome sequencing on five canavanine-resistant S. pombe strains, including the can2-1 mutant isolated in the 1970s. Remarkably, three of these five strains, including can2-1, exhibited loss of over 100 kb of DNA sequence at the left end of chromosome II, a region containing multiple amino acid transporter genes. Interestingly, these three strains underwent chromosome terminal deletion through distinct mechanisms, including homology-driven translocation, homology-independent translocation from ribosomal DNA, and de novo telomere addition. Our findings expand the understanding of the genetic basis of canavanine resistance and reveal diverse mechanisms underlying terminal deletions of chromosomes.