Your maternal aunt has the same mother with your mother. The mtDNA
* is inherited through direct maternal line
* and also is very rarely mutated
It means that there is great probability that you have the same mtDNA with your maternal aunt.
Please don't be confused in questions of differences between mtDNA and atDNA. mtDNA is the DNA located in specific organells of cell called 'mitochondrias'. This DNA is very small and as I said before inherited from the mother. It affects how energy is transformed in our bodies. atDNA is autosomal DNA located in the cell's nucleus. It contains of 22 chromosome pairs and sex chromosomes (XX or XY). They are inherited from both parents and define how we look, feel etc.