Now as to some of the ties, they will need to show that they have significant close family at home, property not easily sold, and a good job for a good company that they have had for awhile that a person would not normally abandon. So if the person is young, without much money or any property, they could be denied.
A mutation can occur anywhere in the body in a cellular level, but mainly if it is a disease, such as a hereditary one, it is usually in the DNA.
Insertion and deletion mutations can be as small as one nucleotide, to thousands of nucleotides long. These long insertion or deletion mutations normally occur when one part of a chromosome crosses over and changes genetic information with a different chromosome. All mutations have the potential to be very damaging, but most are benign.