Researchers compared DNA of remains with that of living Romanov relatives . Results of the DNA analysis were published online Tuesday in the journal PloS One . In 2008 , scientists used bone and tooth fragments to identify the remains as those of the two missing children of Czar Nicholas II : 13-year-old Crown Prince Alexei , the emperor 's only son and heir to the throne , and his sister Grand Duchess Maria , about 19 . The researchers said they found a match between two sets of mitochondrial DNA, which is passed from mother to child and can be traced back through generations, as well as an ancient genetic marker called haplogroup R1b.
Researchers compared DNA of remains with that of living Romanov relatives . Results of the DNA analysis were published online Tuesday in the journal PloS One . The researchers said they found a match between two sets of mitochondrial DNA, which is passed from mother to child and can be traced back through generations, as well as an ancient genetic marker called haplogroup R1b.