It seems only fitting that a podcast series called Along the Backbone should discuss the formation of the backbone in one of lengthiest vertebrates: snakes.Podcast Teaser: Snakes are lizards.  More specifically, snakes are limbless, eyelidless, earless lizards with megakinetic skulls and well-developed salivary glands that often produce venom.  Among the many standout features of snakes, perhaps the most fascinating is how these vertebrates routinely develop a body that will have 120 or more rib-bearing vertebrae and no limbs.  It turns out that a simple but profound difference in the timing of the expression of developmental genes called HOX genes renders snakes limbless, whereas an increase in the frequency of another set of clock-like genes generates their amazing number of vertebrae.Along the Backbone – Episode 3: How Do You Make a Snake?References / Resources:Cohn, M.J., and Tickle, C. 1999. Developmental basis of limblessness in snakes. Nature, Gomez, C. et al. 2008. Control of segment number in vertebrate embryos. Nature, Vonk, F.J., and Richardson, M.K. 2008. Serpent clocks tick faster. Nature, Transcript available upon request.