Meeting Abstract

P2-79   -   Investigating the function of anterior Hox genes in the patterning of arachnid mouthparts Klementz, BC*; Blaszczyk, PO; Gainett, G; Sharma, PP; University of Wisconsin-Madison, Department of Integrative Biology, Madison, WI bklementz@wisc.edu

Comparatively little is known about the function of anterior Hox genes in Chelicerata. Previous investigations of homologs of labial and Deformed in the spider Parasteatoda tepidariorum have shown that these play a role in the patterning of the pedipalpal segment and the identity of the first walking leg, respectively. However, broader inferences are hindered by the existence of duplicate copies of nearly all Hox genes in groups like spiders and scorpions, which have resulted from an ancient whole genome duplication event. Here, we investigated the function of single-copy orthologs of labial, proboscipedia, and Deformed in the harvestman Phalangium opilio, an exemplar of a lineage that was not part of this whole genome duplication. Embryonic RNAi against these genes resulted in loss of function phenotypes only for labial and Deformed. We show that both single-copy genes have a broader function than their spider counterparts, in that both genes affect the identity of two segments. These datasets provide clues to the organization and deployment of Hox genes for anterior head patterning in the common ancestor of the arachnids.