spontaneous changes in genetic material are called what? and the first stage of gene expression is called what?
Mutation.
Since this is not my area of expertise, I searched Google under the key words "'gene expression' 'first stage'" to get these possible sources for your second question:
(Broken Link Removed)
http://books.google.com/books?id=DqcPWlOM63wC&pg=PA336&lpg=PA336&dq=%22gene+expression%22+%22First+Stage%22&source=web&ots=K4Lmz1UU__&sig=l7iIaPcvEoVPK5boUD2VU5Z6zR4&hl=en
In the future, you can find the information you desire more quickly, if you use appropriate key words to do your own search.
I hope this helps. Thanks for asking.