Researchers from Taiwan and the USA have been able to differentiate between some 900 morphogenes and a similar number of physiogenes (out of more than five thousand tested) in genetically modified mice. In the words of co-researcher Jianzhi Zhang:
We found very large differences." Morphogenes were more likely to carry instructions for transcription -- the step that determines whether a gene should be turned on and how much gene product should be manufactured. Physiogenes were more likely to be blueprints for enzymes, receptors, transporters and ion channels (molecules that control the flow of ions across cell membranes).
The finding also seems to seriously challenge some hypothesis that suggested that genes caused both types of effects simultaneously.
The researchers also compared these genes in tissue from different species and found more differences in morphogenes than physiogenes, what means that form evolves effectively faster than function.
Source: Science Daily.
Ref. Ben Yang-Liao et al., Contrasting genetic paths to morphological and physiological evolution. PNAS 2010. (Pay per view depending on world region, should be open access everywhere in six months).