These changes can be caused by environmental factors such as ultraviolet radiation from the sun, or can occur if an error is made as DNA copies itself during cell division. Acquired mutations in somatic cells (cells other than sperm and egg cells) cannot be passed to the next generation.
The parents alleles would be GG and gg. the reason why is if they were both GG they would all be GG. If they were both gg all the offspring would be gg. hope this helps.
