Maria was known to have received topaz jewelry each year for her birthdays. DNA analysis can show who is related to whom but can not identify which sister is which. The case of the Romanovs introduces us to a few of the limitations of current DNA identification techniques used on old remains. Genetic comparisons can determine if a person's remains are related to others, both living and dead, but can not yet determine the degree of the blood relationship. Yes, the person in the grave is related, but science can not yet tell us how.
Positive identification is also problematic with old remains.
The Czar's family was identified because of eyewitness accounts of their execution and burial along with physical evidence found with the remains. DNA analysis confirmed only that the remains were related to other relations of the Imperial Russian house. Another Father of Our Country Recent results published in Nature magazine used DNA testing to support the probability that Thomas Jefferson fathered Sally Hemming's last child. This testing generated much media attention and Jefferson's ideals as a political thinker and his relationships with his slaves were re-examined in the process Lost in the controversy over the author of the Declaration of Independence's liaison with one of his slaves was the DNA testing's ability to disprove an ancestry. The evidential record of who one of the fathers in the Woodson line was supposed to be was incorrect.