Human remains attributed to Tsar Nicholas II, his wife Tsarina Alexandra and his father Tsar Alexander III have recently been unearthed (again) at Peter and Paul Cathedral in St. Petersburg, Russia. Apparently, they are subjected to another round of genetic testing, although a series of DNA tests were performed on the remains by internationally renowned laboratories.
History of most relevant genetic identifications performed in the Romanov case:
First series of DNA analyses
The first experiments conducted on the Romanov remains were published in 1994. This study was supervised by Peter Gill, the leading forensic scientist at the time. Mitochondrial DNA was used to link the remains to Tsar Nicholas II and his wife Alexandra with three of their five children that were all found buried in a mass grave near Yekaterinburg. Mitochondrial DNA is uni-parentally inherited from mother to offspring, which is why it can be used for identification of individuals across multiple generations. Gill and coauthors used samples from present-day relatives as reference, providing very strong evidence, as the authenticity of these individuals was beyond any doubt.
Second series of DNA analyses
In 1996 an independent study was performed by the Armed Forces DNA Identification Laboratory (USA), demonstrating that the remains attributed to Nicholas’ brother Georgii Romanov shared the same mitochondrial DNA as the remains attributed to the Tsar, thus adding evidence to the authenticity of the remains.
Third series of DNA analyses
In 2009 an independent group of Russian scientists confirmed the earlier findings by extending the mitochondrial DNA analysis to modern standards and including the remains of the two so far missing children of the Romanov family. Also, they extended the study to nuclear DNA markers. This study again confirmed the authenticity of the remains.
Fourth series of DNA analyses
The most comprehensive genetic analysis on the Romanov remains was performed by the Armed Forces DNA Identification Laboratory (USA) and the Institute of Legal Medicine, Medical University of Innsbruck in 2009. This study involved the putative remains of the Tsar and his wife as well as those of all five children. The relevant forensic genetic markers were investigated in this study, including mitochondrial DNA, Y-chromosomal DNA and autosomal DNA, which resulted in a scientifically sound identification of all seven individuals, again confirming the earlier studies.
In addition, a blood sample from a shirt of the Tsar was analyzed (that he was wearing during an stab attack in Japan), which resulted in a fully concordant nuclear DNA profile to his remains, providing the strongest evidence possible to achieve in human genetic identification.
In summary, four independent series of scientific test proofed that the remains belong to a family consisting of father, mother and five children. Due to the fact that the DNA results also match present-day living individuals and a direct sample from the Tsar (blood on shirt) no reasonable doubts remain that these individuals belong to the Romanov family.
Recent press articles acknowledge the possibility that the Romanov remains might have been mixed up (with other remains). The fact that the DNA found in the remains belong to seven individuals that are - beyond any reasonable doubt - fitting one family that is further linked to present-day samples related to the Romanov family, leaves this assumptions without any grounds. Any sample mix-up with other samples would result in DNA profiles that lead to an exclusion of relatedness.
The new analyses planned on the remains can only confirm the older results, if the experiments are performed according to forensic standards and if the correct remains are investigated. Generally, the use of alternative reference samples is beneficial, as this would strengthen the evidence. However, the apparent attempt to use the remains of Alexander III, the father of Nicholas II, holds risks: those remains are not as reliable as remains from present-day living individuals. A non-match between the putative remains of Alexander III and Nicholas II would not dismiss the existing evidence, as other scenarios could explain such results.
- Gill, P. et al. Identification of the remains of the Romanov family by DNA analysis. Nature Genetics 6, 130-135, doi:10.1038/ng0294-130 (1994).
- Ivanov, P. L. et al. Mitochondrial DNA sequence heteroplasmy in the Grand Duke of Russia Georgij Romanov establishes the authenticity of the remains of Tsar Nicholas II. Nature Genetics 12, 417-420, doi:10.1038/ng0496-417 (1996).
- Rogaev, E. I. et al. Genomic identification in the historical case of the Nicholas II royal family. Proceedings of the National Academy of Sciences of the United States of America 106, 5258-5263, doi:10.1073/pnas.0811190106 (2009).
- Coble, M. D. et al. Mystery solved: the identification of the two missing Romanov children using DNA analysis. PloS one 4, e4838, doi:10.1371/journal.pone.0004838 (2009).