Adriaan Dorresteijn

TL;DR: Comparative analysis indicates that both types of photoreceptors, with distinct opsins, coexisted in Urbilateria, the last common ancestor of insects and vertebrates, and sheds new light on vertebrate eye evolution.

TL;DR: Analysis of expression of conserved eye specification genes in the early development of larval and adult pigment-cup eyes in Platynereis dumerilii indicates that polychaete six1/2 expression outlines the entire visual system from early developmental stages onwards and ath-positive clusters generate the first photoreceptor cells to appear.

TL;DR: Lifelong proliferation of uniform trunk segments qualifies Platynereis as a model for the study of gene expression and of the functional circuitry of this process and can also become a stepping stone in the comparison of segmentation between annelids and arthropods.

TL;DR: The expression patterns of genes orthologous to the arthropod segmentation genes engrailed and wingless in the annelid Platynereis dumerilii are reported as molecular evidence of a segmented ancestor of protostomes.

TL;DR: The formation of symmetry and the nature of the body axes in the embryo and adult of Platynereis dumerilii are discussed and five major compartments can be distinguished which together compose the body of the young worm.