Changes

==Classes of mutations==

==Classes of mutations==

DNA is not a static entity.  It is subject to a variety of different types of heritable change (mutation).  Large-scale chromosome abnormalities involve loss or gain of chromosomes, or breakage and rejoining of chromatids.  Smaller scale mutations can be grouped into different mutation classes according to the effect on the DNA sequence.  Mutations can also be categorized on the basis of whether they involve a single DNA sequence or whether they involve exchanges between two allelic or non-allelic sequences.    According to molecular pathology, there are three main classes of mutation with several subclasses: deletions, insertions and substitutions.   

DNA is not a static entity.  It is subject to a variety of different types of heritable change (mutation).  Large-scale chromosome abnormalities involve loss or gain of chromosomes, or breakage and rejoining of chromatids.  Smaller scale mutations can be grouped into different mutation classes according to the effect on the DNA sequence.  Mutations can also be categorized on the basis of whether they involve a single DNA sequence or whether they involve exchanges between two allelic or non-allelic sequences.    According to molecular pathology, there are three main classes of mutation with several subclasses: [[deletion]]s, [[insertion]]s and [[substitution]]s.   

===Deletion mutations===

===Deletion mutations===