Meeting Abstract
In vertebrates, body size is primarily regulated through the actions of growth hormone (GH), Insulin-like growth factors, and their receptors. The current work compares the coding region of insulin-like growth factor-1 (IGF-1) sequences among three closely related Anolis lizards varying in body size. Two species, Anolis sagrei and A. carolinensis, are relatively small bodied anoles with similar snout-vent lengths and IGF-1 sequence data for both species is available through GenBank. The third species, A. equestris, is a large-body anole for which IGF-1 sequences have not been reported. For all three species total liver RNA was extracted and reverse transcribed to cDNA and then amplified using IGF-1 specific primers. In both A. sagrei and A. carolinensis, a single PCR product of appropriate length was generated. In A. equestris, two products were detected; one similar in size to that of the other anole species, and one longer. The functional significance of the two IGF-1 isoforms observed in A. equestris is unknown, but raises the possibility that evolutionary changes in body size in this species result from differential expression or regulation of IGF-1.
