Phenotypic Plasticity
- Phenotypic plasticity is the idea that although genotype remains fixed throughout an organism's lifetime, the way that the phenotype is expressed can vary during this time
- An organism’s internal or external environment can influence gene expression patterns, and therefore phenotype
- The levels of regulatory proteins or transcription factors can be affected in response to environmental stimuli such as light, and chemicals including drugs and hormones
- For example, enzymes are activated in response to ultraviolet radiation and increase the expression and production of melanin, leading to skin pigmentation
- Temperature can also influence gene expression as demonstrated by organisms
- The Himalayan rabbit (Oryctolagus cuniculus L.) possesses a gene for the development of pigmentation in its fur
- The gene is inactive above 35°C but active between 15°C and 25°C
- In the parts of the body that are cooler such as ears, feet and nose the gene becomes active making these areas black
- The Himalayan rabbit (Oryctolagus cuniculus L.) possesses a gene for the development of pigmentation in its fur