Nucleotide diversity and amino acid variants in the ZmIPT2 coding region. (A) The full sequence of ZmIPT2 gene. Sites are labeled according to the position of the corresponding polymorphisms in the aligned sequences, with amino acid alterations indicated in parentheses. The gray box indicates the IPT domain, which starts at position 28 and ends at position 480. (B) The ZmIPT2 genomic sequences grouped into seven haplotypes defined by 16 single nucleotide polymorphisms identified in the alignment.