Among the echinoderms, members of the subphyla Echinozoa (sea urchins and sea cucumbers) express the major yolk protein (MYP) but not vitellogenin (Vtg), while an initial report has documented that two Asterozoa (sea stars) express a vitellogenin.
Much of the research on yolk proteins in echinoderms has focused on the Echinozoa subphylum and less on the Asterozoa subphylum.
The current literature suggests that the Echinozoa subphylum of echinoderms expresses MYP (Brooks and Wessel, 2002; Unuma et al., 2003, 2007; Yokota et al., 2003), while the Asterozoa subphylum expresses the Vtg protein, Vtg1 (Prowse and Byrne, 2012).
exigua, may shine light on the evolution of yolk proteins in the echinoderm subphylum, Asterozoa. Asterozoa phylogeny based on mitochondrial DNA (mtDNA) indicates that P.