The change in the genetic sequence of the organisms known as mutation. Mutations might be sudden and heritable in nature. spontaneous mutation and induced mutation are types of mutation.
A change that causes a change in single base pair of a gene sequence is called substitution mutation. The original leucine sequence is GTT and the mutated sequence is GTG. Thus T has been substituted by G.
Mutation can be beneficial, detrimental or neutral. The neutral mutation is that does not affect the physical change. Both GTT and GTG code for the same amino acid so it would be neutral.
a. We will see DNA fragments with 145-200 bps (only one band)
b. The DNA sequence linked to histones will be protected from the action of DNase I, thereby this enzyme only can cut linker DNA (i.e., 55 bp fragments). In consequence, it is expected to observe a single band with a length of approximately 145 to 200 base pairs