Origin, conservation, and loss of alternative splicing events that diversify the proteome in Saccharomycotina budding yeasts

Alternative splicing of YSH1/SYC1 orthologs in the Saccharomycotina. (A) Splicing pattern is shown for each of the species analyzed, along with the species phylogeny as in Figure 1A. Black asterisks indicate that Z. rouxii and N. castellii appear to have lost Syc1. (B) C. jadinii diverged before the likely origin of YSH1/SYC1 alternative splicing and its ortholog contains a constitutive intron. (C) Alternative 3′ splice sites in the YSH1/SYC1 ortholog of L. kluyveri, as previously reported. (D) Alternative 3′ splice sites in the YSH1/SYC1 ortholog of T. blattae. (E,F) Duplicated YSH1 and SYC1 genes in S. cerevisiae lack introns.