DNA sequences and distinct mechanisms for  ura4-595  and  ura4-294  alleles of  S. pombe .
The  ura4  gene of the fission yeast  Schizosaccharomyces pombe  supports both positive and negative selection; consequently, this gene is widely employed as a powerful tool to study diverse biological processes. Here we report the DNA sequences of two functionally null alleles,  ura4-595  and  ura4-294  . The  ura4-595  allele has a four bp duplication of bp +63 to +66 (5'-CAAG-3') within the ORF and the  ura4-294  allele has a nonsynonymous substitution (G to A) at bp +679. We infer that these alleles arose, respectively, by DNA polymerase template slipping and by nucleotide misincorporation (likely via cytosine deamination).
Protacio RU, Malone EG, Wahls WP