2.2 Sequence analysis
The protein sequence of Human Iroquois family members like IRX1 (P78414), IRX2 (Q9BZI1), IRX3 (P78415), IRX4 (P78413), IRX5 (P78411) and IRX6 (P78412) were retrieved from UniProt (accession numbers in brackets). IRX4 (P78413) is a 519 amino acid long protein with DNA binding region, in positions 143-204. The homeodomain consists of 62 amino acids in the IRX4 protein. Multiple sequence alignment and phylogenetic tree analysis of IRX family members was performed using Clustal Omega 39. The 62 amino acid homeodomain sequence was checked for mutations in the region using the Catalogue of Somatic Mutations in Cancer (COSMIC) database 40.