Introduction : Evolution of the mammalian heart from the simple contractile tube used in ancestral species for nutrient dispersal into a complex, multi-chambered organ as seen in mammals, relied on a conserved network of transcription factors. The discovery of these factors has been an area of intense interest over the last two decades. The identification of genes encoding cardiac transcription factors from a number of invertebrate and vertebrate species has revealed an underlying genetic architecture of cardiac development that dates back over 500 million years to prior to the emergence of the bilateria (Cripps and Olson, 2002; Davidson and Erwin, 2006). An ancient gene regulatory network (GRN) acts to specify the regulatory state within a cohort of cells, and further participates in morphogenesis of the final organ. Importantly, in terms of the evolution of cardiac structures, the core transcriptional network, or ?kernel?, is inviolate, as removal of one component of the kernel leads to catastrophic effects on heart development (Davidson and Erwin, 2006). In retrospect, cardiac developmental biologists have benefited greatly from the observation that, despite the gross morphological variation in the hearts of different phyla (Fig. 1), the fundamental genetic circuitry is relatively inflexible and, therefore, highly conserved. A prominent example of this was the discovery that members of the NK-2 class of homeobox genes are essential for cardiac development in both Drosophila and vertebrates (Azpiazu and Frasch, 1993; Bodmer, 1993; Lyons et al., 1995; Cleaver et al., 1996).
|Title of host publication||Heart Development and Regeneration, Volume 1|
|Editors||Nadia Rosenthal, Richard P Harvey|
|Place of Publication||UK|
|Pages||571 - 599|
|Number of pages||29|
|Publication status||Published - 2010|