Explanation:

• The technique involved in producing a mouse of over eight times its normal size by introducing a human growth hormone gene is called genetic engineering or transgenic technology.
• This process involves manipulating an organism's genome using biotechnology to introduce or alter specific genetic material.
• In this case, a human growth hormone gene is inserted into the genome of a mouse, leading to an increase in its size.
• This type of genetic modification is often used in research to study gene functions and their effects on organismal biology.