How do you alter the genes in the mice?

Question: How do you alter the genes in the mice?
- Keywords:
  animal testing,
  gene
Asked by katiechip98 to Mel on 13 Mar 2013.
- Melissa Brereton answered on 13 Mar 2013:
  
  It is a really long and complicated process. Essentially you take the DNA code from the mouse that you are interested in, lets say we want to alter the genes that are important in determining the fur colour, and you use really complicated genetics to change the order of the DNA that will cause the mouse’s fur to change to the colour white. You can then inject this DNA into the unfertilised egg of another mouse and eventually the babies born from this egg will have the new fur colour.

Question: How do you alter the genes in the mice?