Intra-species comparisons

Avian beaks show extreme species-specific variability in morphology, though they develop from the same primordial structures. In both humans and birds, cranial neural crest cells are the primary source of mesenchyme for the frontonasal prominence; previous work has shown that these cells contain molecular information that regulate species-specific facial variation. To determine the molecular basis of avian craniofacial patterning, we have gene expression profiled micro-dissected cranial neural crest cells from the frontonasal prominence of three bird species (chickens, quails, and ducks) during embryonic development. These changes in gene expression were measured on a custom built, cross-species, long oligonucleotide microarray that interrogates the vast majority of transcription factor (TF) genes plus a wide variety of signaling pathways. Samples were isolated at two developmental stages, before (Hamburger Hamilton stage [HH] 20) and after (HH25) morphological distinctions between the species are evident. Keywords: developmental time point comparison Frontonasal mesenchymal cells were micro-dissected two developmental stages, before (Hamburger Hamilton stage [HH] 20) and after (HH25) morphological distinctions between the species are evident. For each sample, mesenchyme from 40 embryos was pooled. For each species, the early stage of development was compared to the later stage. Experiments include technical replicates as well as dye-switches for a total of 4 microarrays per species.