Gap gene

A gap gene encode transcription factors in a developing embryo. They fall under the class of segmentation genes that are expressed during embryonic morphogenesis. Mutations in gap genes are responsible for the loss of contiguous body segments. Evolutionary biologists and molecular cell biologists, study morphogenesis by observing the effects of mutations in the process of development. From experiments that studied these effects in the common fruit-fly (scientific name; Drosophila melanogaster), four gap genes have been characterised; "Kruppel", "giant", "hunchback" "tailless" & "knirps".Each of these genes are expressed in characteristic regions of the developing embryo under the control of maternal effect genes such as "bicoid" and "nanos"