7 Genetic Dissection
of Heart Development
J.-N. Chen and M. C. Fishman
7.1
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 107
7.2
Heart Field ........................................... 109
7.3
Chamber Formation .................................... 112
7.4
Cardiac Laterality. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 114
7.5
Organogenesis Screen. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 116
7.6
Cloning Zebrafish Mutations ............................. I 17
7.7
Conclusion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. I 18
References .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. I 18
7.1 Introduction
Genetic analysis has been a powerful tool to identify genes and pathways in early patterning and cell fate determination in Drosophila and
Caenorhabditis elegans (Nusslein-Volhard 1994). Lacking a vertebrate
model system for large-scale genome-wide screens has limited a direct
genetic approach toward vertebrate pattern formation in the past. Luckily, gene functions and pathways are often conserved from invertebrates
to vertebrates and studying these pathways has been fruitful in understanding vertebrate pattern formation. Some of the best known examples
include the role of the hox genes in patterning the vertebrate nervous
system, the TGF-~ family and wnt signaling pathways in dorsoventral
patterning, and the hedgehog pathway in nervous system and limb