KAVANAGH, K.D.*; MORGAN, B.A.: Regulating differentiation in vertebrates: Functional homology and evolutionary co-option in Ikaros family genes

The Ikaros gene family of transcription factors is important in several vertebrate developmental pathways. Four paralogous genes in the family encode proteins that homo- and heterodimerize before binding to the DNA molecule, facilitating transcription of lineage-specific genes. In the working model for the function of these genes, the proteins act sequentially to regulate the progress of differentiation along a cell lineage, with different Ikaros-family genes expressed as the cells become more restricted in differentiation potential. Recent studies demonstrate that in vertebrates, the genes are expressed and/or function in diverse tissues, including neural, epidermal, and haematopoietic lineages. Progress in understanding taxon-specific and tissue-specific differences and similarities in expression and function will be presented with an evolutionary perspective.