Investigating the regulation and function of gap and Hox genes during segmentation in a short germ insect (360G-Wellcome-109147_Z_15_A)

Three of the most abundant and diverse animal phyla - the Arthropoda, Annelida, and Chordata - are segmented along their anterior-posterior axis. Embryos of the fruit fly Drosophila form all of their segments simultaneously. In contrast, most arthropods, and all vertebrates and annelids, produce the majority of their segments sequentially. Although the molecular and genetic mechanisms regulating simultaneous segmentation have been well-characterised, our understanding of the mechanisms regulating sequential segmentation, especially in arthropods, remains poor. Gap genes are among the best-characterised components of the segmentation cascade in Drosophila. They are also expressed during segmentation of sequentially-segmenting arthropods. In Drosophila, gap genes define broad regions of the embryo; however, in sequentially-segmenting arthropods, they appear to have a different role, possibly mediated via Hox genes. Determining their function in sequential segmentation may shed light on how this developmental process is regulated, and how it was modified to give rise to simultaneous segmentation. For my PhD, I therefore propose to investigate the expression patterns, interactions and functions of gap and Hox genes in a simultaneously-segmenting arthropod, Tribolium castaneum. To accomplish these goals, I will analyse gene expression, cell behaviours and embryonic development in wild type and genetically manipulated Tribolium embryos.