TYPICAL MUTATIONS

    This graphic is a hypothetical representing the male descendants of 1 man over 4 generations  and theY chromosome mutations possible. The letters a and b represent the first and second son respectively.

    Blue colour shows those sons with no mutations from the common ancestor.
  Brown colour shows those sons with a mutation increase of 1 at one marker only, say  to 30 at marker 449, commencing at the second son in generation 2
  Orange colour shows those with a mutation decrease of 1 at one marker only, say to 18 at marker 448.
  Red colour shows a decrease of 2 in a single step mutation at one marker only, say to 12 at marker 437.

    Common Ancestor

With all other markers matched we have 3 x 23/25 matches

    Note that mutations occur randomly at any one marker once in about 500 generations (say 10,000 to 15,000 years), and so, in 25 marker tests, are encountered once in about 20 generations or say 500 years. A single step mutation of 2 would be even rarer. Mutations may be negative (deletions) or positive (insertions).