CROTWELL, P.L.*; MABEE, P.M.; Univ. of South Dakota, Vermillion; Univ. of South Dakota, Vermillion: Co-option of genetic regulatory mechanisms? From fish segments to mouse joints. We have hypothesized that the mechanisms underlying radial segmentation in fishes may have been co-opted over several million years of evolution to give rise to tetrapod synovial joints. Radials are […]

DAVIDSON, B. J.; LEVINE, M.; Univ. of California, Berkeley: Chordate CPR: Resuscitating the exploration of chordate heart evolution The most primitive chordate heart is found in the tunicates. Although rudimentary in structure, the tunicate heart is similar to vertebrate hearts in morphogenesis and embryological origins. Recent research has characterized many of the essential genes which […]

MINSUK, S.B.*; RAFF, R.A.; Dept. of Biology, Indiana University, Bloomington: A New Angle on Axial Patterning: Co-option of a Dorsal-Ventral Patterning Mechanism to Control Left-Right Differentiation in a Direct-Developing Sea Urchin Axial patterning is a central question in developmental biology. In sea urchins it is not known how the dorsoventral (DV) and left-right (LR) larval […]

REITZEL, Adam M; MINER, Benjamin G; Boston Univ.; Univ. of Florida: Transitions in Marine Invertebrate Life Histories: Reduced Planktotrophy in an Echinoid Larva Lecithotrophic development has evolved from planktotrophic development numerous times in many marine invertebrates and is generally considered to be irreversible. Lecithotrophic larvae develop from relatively large yolky eggs that provide the organism […]

MCGHEE, Katie/E; Florida State University, Tallahassee: Indiscriminate fusion of swimming sponge larvae For sedentary marine invertebrates, allorecognition systems allow individuals to distinguish between genetically similar and distinct tissue they may encounter and are thought to reduce tissue fusion with individuals other than self or kin. However, the cost/benefit trade-offs associated with fusion at a sessile […]

LASKER, H.R.*; GUTIERREZ-RODRIGUEZ, C.; University at Buffalo; University at Buffalo: Fertilization and local gamete dispersion in a surface brooding gorgonian Colonies of the Caribbean gorgonian Pseudopterogorgia elisabethae release unfertilized eggs that are retained on the colony surface where they are fertilized and develop into planulae. On San Salvador, Bahamas spawning starts in the week following […]

PERNET, Bruno; Friday Harbor Laboratories, Washington: Evolutionary persistence of feeding structures in nonfeeding annelid larvae The requirement for feeding during the larval stage has been lost in many lineages of marine invertebrates. This evolutionary transition in nutritional mode is often followed rapidly by changes in larval morphology, in particular reduction or loss of structures involved […]