Gap gene

A gap gene is a type of gene involved in the development of the segmented embryos of some arthropods. Gap genes are defined by the effect of a mutation in that gene, which causes the loss of contiguous body segments, resembling a gap in the normal body plan. Each gap gene, therefore, is necessary for the development of a section of the organism.Expression of tailless is activated by torso protein in the poles of the embryo. Tailless is also regulated in a complex manner by the maternal-effect gene bicoid.The gap genes code for transcription factors that regulate the expression of pair-rule genes and homeotic genes by competing for binding to their enhancer regions.It has been demonstrated that gap gene expression in the Drosophila blastoderm exhibit a property called as canalization, a property of developing organisms to produce a consistent phenotype despite variations in genotype or environment. It has been recently proposed that canalization is a manifestation of cross regulation of gap genes expression and can be understood as arising from the actions of attractors in the gap gene dynamical system