mtdna

[james.england]

If myself and my brother or sister had the exact same dna match what would be the maximum centimorgan number shown in match. As we look in relatives matches I wonder what is the maximum number value that can be obtained for a full dna match. If anyone can help it would be greatly appreciated.
Thanks.

[prairielad]

If referring to an exact mtdna match, then cM is not used. An exact mtdna match would be shown a 0 GD (Genetic Distance).
MTDNA is not part of the chromosomal DNA. It is a seperate source of DNA with in a cell that is only passed on by mother's.

Are you referring to XDNA, which is part of the 23rd chromosome pair?
MTDNA and XDNA are two seperate sources of DNA with different inheritance patterns.
If so full matching on the X chromosome is roughly 196cM