Gene structures of Kunitz/BPTI proteins and their distributions in the genome. (A), Gene structures of Kunitz/BPTI proteins. The gene structures of single and multi-domain Kunitz/BPTI proteins show similar characters. Exons were colored with green and numbered below. SP: signal peptide; KU: Kunitz/BPTI domain; (B), the distributions of Kunitz/BPTI gene. Some Kunitz/BPTI genes are arranged in tandem in the genome. Genes were colored with green.