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9bp deletion

From ISOGG Wiki

The nine base pair deletion (9bp deletion) is a common mutation seen in mitochondrial DNA sequences. It occurs in the coding region between positions 8281 and 8289. The sequence will appear in the mutation list as:

At this region in the mtDNA genome there is a nine base pair sequence that repeats two or three times. It's like a very short, but giant STR, and it has a tendency to mutate in repeats rather than in a single position. Sometimes the mtDNA loses a repeat (the 9bp deletion) and sometimes the mtDNA adds a repeat (9bp insertion). The deletion is seen in nearly all of haplogroup B and it also occurs at random in other haplogroups.[1] Three examples of the 9bp deletion have been found in the mtDNA haplogroup U4 project as of January 2015.[2]

The deletion should be treated as a single mutation but is not currently treated as such by the Family Tree DNA mtDNA matching algorithms.


  1. Murphy E, Data Assurance, Family Tree DNA. Personal communication to Debbie Kennett, 29 March 2013.
  2. .Kennett D, Group Administrator, mtDNA Haplogroup U4 Project, 10 January 2015.

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