Environmental Influence on Genes The external and internal Environment influences how a gene is expressed or if it is expressed

External Environment Temperature, nutrition, light, chemical, and infectious agents can influence gene expression EX: Himalayan Rabbit

Himalayan Rabbit Its genotype says that all the fur should be black The enzyme that produces the black pigment only functions at temperatures below 93°F. The nose, ears, tail, and feet, are in contact with cold enough temperatures to “activate” the enzyme

If you were to put an ice pack on a Himalayan rabbit, the hair would grow in black The gene would be expressed, based on environmental conditions

Internal Environment Internal environment of males and females are different because of hormones and structural differences The difference in hormones, and amount of hormone is determined by sets of genes

EX: Male pattern baldness and feather colors in peacocks Male Female