Transcriptome analysis of ectopic expression of alx1 gene in starfish embryo. Patiria pectinifera

Larval skeleton is one of the remarkable traits for some echinoderm classes, such as sea urchin and brittle star. Larval skeleton is thought to be a derived trait in these classes. A transcription factor Alx1 is known to be an important component of skeletogenic gene regulatory network (GRN) in sea urchin larva. We found that starfish larva, which has no skeleton, did not express alx1. Thus, we hypothesized that the acquisition of embryonic expression of alx1 was involved in the acquisition of larval skeleton. In order to test the probability of the hypothesis, we artificially overexpressed sea urchin alx1 in starfish embryos as a experimental replication of the evolutionary step. RNAseq was conducted to detect changes in gene expression in this sample.