Epinephrine
Epinephrine is usually produced by the two kinds the adrenal
glands and certain neurons. It plays an
important role in the fight-or-flight response by increasing blood flow and
also to muscles, output of the heart, pupil dilation, and blood sugar.
The gene responsible for lactose persistence among adults in Europe is a regulatory gene.
DNA is a dynamic and adaptable molecule. As such, the nucleotide sequences found within it are subject to change as the result of a phenomenon called mutation. Depending on how a particular mutation modifies an organism's genetic makeup, it can prove harmless, helpful, or even hurtful.
Mutation (A)
