Comparative analysis of gene expression patterns in the arthropod labrum and the onychophoran frontal appendages, and its implications for the arthropod head problem.

ABSTRACT: The arthropod head problem has troubled scientists for more than a century. The segmental composition of the arthropod head, homology of its appendages, and especially the nature of the most anterior region of the head are still, at least partially, unclear. One morphological feature of the head that is in the center of current debate is the labrum (upper lip), a fleshy appendicular structure that covers the arthropod mouth. One hypothesis is that the labrum represents a fused pair of protocerebral limbs that likely are homologous with the frontal appendages (primary antennae) of extant onychophorans and the so-called great appendages of stem arthropods. Recently, this hypothesis obtained additional support through genetic data, showing that six3, an anterior-specific gene, is exclu

SUBMITTER: Janssen R 

PROVIDER: S-EPMC5209905 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature