Domain-Shuffling in the Evolution of Cyclostomes and Gnathostomes.

Vertebrates acquired various novel traits that were pivotal in their morphological evolution. Domain shuffling, rearrangements of functional domains between genes, is a key molecular mechanism in deuterostome evolution. However, comprehensive studies focusing on early vertebrates are lacking.

Development of the vertebra and fin skeleton in the lamprey and its implications for the homology of vertebrate vertebrae.

Background: Although vertebrae are the defining character of vertebrates, they are found only in rudimentary form in extant agnathans. In addition, the vertebrae of agnathans possess several unique features, such as elastin-like molecules as the main matrix component and late (post-metamorphosis) differentiation of lamprey vertebrae. In this study, by tracing the developmental process of vertebrae in lamprey, we examined the homology of vertebrae between lampreys and gnathostomes.