Figure 5.

Schematic of key events in the evolution of TIMP genes in deuterostomes. After the split between Protostomia and Deuterostomia, there was a diversification of TIMPs which persisted into the five echinoderm classes (I). One early TIMP lineage was inherited by the ancestor of all chordates and is the progenitor of TIMPs 1–4 studied in vertebrates (II), and its sister lineage diversified and continued into the echinoderms (III). Of this latter lineage, one copy diversified much later in holothuroids, giving rise to the tensilin gene (IV).