Comparison of the MUC13 sequence in man and chicken. A. Genomic organization of exons and introns and the domains encoded by the exons. B. Amino acid sequences of the PTS (mucin) domains of the chicken and human MUC13. For the chicken PTS each line corresponds to one exon. C. Alignment of the amino acid sequence C-terminal of the PTS domain. Identical and similar amino acids are indicated with black and grey, respectively, and domains are shown under each sequence.