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http://www.sciencemag.org/cgi/reprint/306/5695/407b.pdf

Ongoing Controversy
over Romanov Remains
THE FIELD OF ANCIENT DNA ANALYSIS HAS
faced numerous obstacles and setbacks in
its path to legitimacy. Yet another setback
was showcased in the news story “Buried,
recovered, lost again? The Romanovs may
never rest” (R. Stone, News Focus, 6 Feb.,
p. 753). Much was made of a report by
A. Knight et al. (1) that claimed to be a failed
attempt to “replicate the findings” of a
previous DNA analysis of the putative remains
of Tsar Nicholas II of Russia, the Empress
Alexandra, and three of their daughters (2).
Knight et al. did not, in fact, test the
skeletal material in question, but used a new
maternal reference sample for Alexandra:
an 86-year-old finger putatively from
Alexandra’s sister, Grand Duchess Elisabeth
of Russia. We cannot see why anyone would
consider this a superior DNA source to the
modern-day blood sample from Alexandra’s
grandnephew Prince Phillip of Great Britain
that was analyzed previously. Moreover, the
finger showed a mixture of mitochondrial
DNA (mtDNA) sequences from different
individuals, and in two of four amplifications
showed a minority sequence that
matched a rare sequence motif shared by
Prince Phillip and Alexandra. The results of
Knight et al. end in a fizzle. The fuss has
been caused by their claim that recent developments
in the ancient DNA field (3, 4)
constitute “certain evidence” of the fallacy
of the Gill et al. (2) testing, because of
amplicon sizes involved.
This bald assertion naively elevates a wellestablished
truism of ancient DNA—that it is
fragmented in length—to categorical law,
ignoring the breadth of ancient/forensic DNA
literature and experience and the range of
considerations that are part of determining
ancient DNA authenticity. Knight et al.
repeatedly assert that DNA fragments greater
than 250 base pairs (bp) do not exist in
samples as little as 70 years
old. However, DNA preservation
depends on both the
age of a sample and the
environmental context, with
comparatively cold temperatures
greatly favoring DNA
preservation (5, 6). Instances
of remarkable preservation
include recovery of a 1.7-kb
fragment of a single-copy
gene from a 156-year-old
dried specimen (7), 1.6 kb
from 560-year-old avian
bones (8), and 438 bp from a
3350-year-old moa bone (9).
Successful amplification of
522 bp of mtDNA from
a 20,000-year-old ground
sloth coprolite from Utah
(10) suggests that amplification
of DNA fragments twice
that length from bones
300 times younger is far
from implausible. Moreover,
Knight et al. fail to acknowledge
that the 1223-bp amplicons of Gill et al.
(2) were used only in the first round of a 62-
cycle nested PCR protocol.
We explored the use of nested and nonnested
PCR on six degraded skeletal
extracts of known authentic sequence:
~60-year-old bones of three individuals
recovered from a crash in temperate coastal
Alaska (from a lower latitude than the
Romanov remains) and three from
temperate Asia (~50 years old). Using standard
single round PCR, we did, in fact,
obtain successful PCR and authentic
sequence with 1200-bp amplicons for two
of the three Alaska bones, but not with any
others. However, when a nested protocol
similar to Gill et al. (2) was employed using
1200-bp primers in the first round and
221-bp primers in the second, we obtained
authentic sequence from all three Alaskan
bones and two of the Asian bones. These
results suggest there is nothing implausible
about the results of Gill et al. (2).
Tsar Nicholas II of Russia, his wife Empress Alexandra, and
their five children, circa 1907.
LETTERS
Published by AAAS
on February 22, 2007 www.sciencemag.org Downloaded from
L E T T E R S
15 OCTOBER 2004 VOL 306 SCIENCE www.sciencemag.org
Knight et al. fail to cite the replication
of mtDNA results of the Tsar in an independent
laboratory with different methods
(11), an important criterion of ancient
DNA authenticity. Furthermore, another
criterion of ancient DNA authenticity in the
Romanovs is also met: The results make
sense in the genetic context of the investigation.
The nuclear short tandem repeats
(STRs) are consistent with a mother, father,
and three daughters, and there is an
mtDNA link of the mother to Prince
Phillip, an mtDNA link of the father to
living relatives, and shared heteroplasmy
with the Tsar’s brother (11). The chances
that these results are from contamination
are astronomically slim.
As no reasonable alternate explanation
for the data is apparent, or has been offered,
we conclude that there is no scientific
reason to refute the identification of
the Romanovs. Although ancient DNA
research will always remain prone to artifacts
because of contamination, requiring
carefully conducted studies, it should not
be put out of the realms of science into
some mystic sphere where generalized
criteria suggested in review articles are
used as dogma to refute otherwise indisputable
scientific results.
MICHAEL HOFREITER,1 ODILE LOREILLE,2
DEBORAH FERRIOLA,2 THOMAS J. PARSONS2
1Max Planck Institute for Evolutionary Anthropology,
Deutscher Platz 6, D-04103 Leipzig,
Germany. 2Armed Forces DNA Identification
Laboratory, 1413 Research Boulevard, Rockville,
MD 20850, USA.

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