Gene conversions may obscure actin gene family relationships.

Phylogenetic hypotheses of muscle actin evolution are significantly different when a sea urchin is used as a representative echinoderm than when a sea star is used. While sea urchin muscle actins support an echinoderm-chordate sister relationship, sea star sequences suggest that echinoderm muscle actins are convergent with chordate muscle actins. Our results suggest that gene conversion in the sea star muscle actin may be responsible for these discordant results.