Rise of the Animal Kingdom and Epigenetic Mechanisms of Evolution - Building the Most Complex Structure on Earth - page 290

behavior ( Palmer et al., 2007 ). If the nervous system recruits the gene in development,
why cannot it have recruited the same gene in P. shermani 27 million years ago?
Butterflies of a number of families determine their pupal body color based on the
color of the pupation background for the purpose of avoiding predation during this
sessile stage of life. The pupae of Papilonidae on dark background secrete the neu-
rohormone pupal melanization-reducing factor (PMRF) that determines their dark
body color. On light or green vegetation backgrounds, they do not produce the neu-
rohormone and display green-yellowish color ( Starnecker and Hazel, 1999 ). In both
cases, the coloration is adaptive.
Pupae of the Pieridae and Nymphalidae families on a dark background do not
release the neurohormone and display dark color. The reverse occurs on a light
colored background, where pupae secrete PMRF but develop a light body color.
The mechanism of PMRF secretion is a neural mechanism: the visual stimuli on the
background are transmitted to the brain, where the color is perceived and the neuro-
hormone is released by secretory neurons.
In all the representative cases presented above, the recruitment of the gene/gene
product in the relevant pathways is under neural control and this neural mechanism
may have been operative since these insects evolved this diphenism ( Cabej, 2011 ).
References
Aboobaker, A., Blaxter, M., 2010. The nematode story: Hox gene loss and rapid evolution.
Adv. Exp. Med. Biol. 689, 101-110.
Alie, A., Manuel, M., 2010. The backbone of the post-synaptic density originated in a unicel-
lular ancestor of choanoflagellates and metazoans. BMC Evol. Biol. 10, 34.
Ament, S.A., Wang, Y., Robinson, G.E., 2010. Nutritional regulation of division of labor in
honey bees: toward a systems biology perspective. Syst. Biol. Med. 2, 1-11.
Ayala, F.J., 1997. Vagaries of the molecular clock. Proc. Natl. Acad. Sci. U.S.A. 94, 7776-7783.
Ayala, F.J., Rzhetsky, A., Ayala, F.J., 1998. Origin of the metazoan phyla: molecular clocks
confirm paleontological estimates. Proc. Natl. Acad. Sci. U.S.A. 95, 606-611.
Baldock, P.A., Sainsbury, A., Couzens, M., Enriquez, R.F., Thomas, G.P., Gardiner, E.M.,
et al., 2002. Hypothalamic Y2 receptors regulate bone formation. J. Clin. Invest. 109,
915-921.
Beisson, J., Sonneborn, T.M., 1965. Cytoplasmic inheritance of the organization of the cell
cortex in Paramecium aurelia . Proc. Natl. Acad. Sci. U.S.A. 53, 275-282.
Bengtson, S., 2002. Origins and early evolution of predation. Paleont. Soc. Papers 8, 289-317.
Bengtson, S., Belivanova, V., Rasmussen, B., Whitehouse, M., 2009. The controversial
“Cambrian” fossils of the Vindhyan are real but more than a billion years older. Proc.
Natl. Acad. Sci. U.S.A. 106, 7729-7734.
Bery, A., Cardona, A., Martinez, P., Hartenstein, V., 2010. Structure of the central nervous sys-
tem of a juvenile acoel, Symsagittifera roscoffensis . Dev. Genes Evol. 220, 61-76.
Bownds, D., 2001. Layers of brain. Available from: < http://dericbownds.net/bom99/Ch03/
Ch03.html >
Bromham, L., 2009. Molecular dates for the Cambrian explosion: is the light at the end of
tunnel an oncoming train? Palaeontologia Electron. 9 (2E), 3. Available from: < http://
palaeo-electronica.org/2006_1/editor/focus.htm >