I do not know of very many creationists who believe that way. Noah's Ark. Each of the animals on the ark contained the full genetic potential for all of the species and subspecies found in the earth. Given that, we do dispute that microevolution can produce new genetic information. In fact, we believe that the trend we observe is the deletion of genetic information through mutations, and not the production of new genetic information. A point mutation may result in the expression of a trait that is normally recessive or hidden were it not for the fact that a dominant gene is altered.
Most mutations observed by scientists are detrimental to the organism.
Much like a computer program that has been altered accidentally with one letter missing or changed, a genetic code sequence that has been damaged will result in a subroutine that will not function as expected. Since there is so much redundancy built into the master plan of life, some damage of this sort may not be detrimental, but it may result in other biochemical processes taking over. Similarly, if you cut off someone's finger, it won't usually result in the loss of life. The person may continue to live quite well with four fingers. But such damage will not result in offspring with four fingers.