|
|
|
Pages in this article: [ UNRAVELLING
THE MUMMY ]
[ IDENTIFYING THE MUMMIES ] [ X-RAYING THE MUMMIES ] [ USING DNA ]
Using DNA
|
With the advances in science
technology, there is now a new "weapon" that can help Egyptologists in
their quest to construct the definitive chronology of Egyptian kings, namely DNA
testing. The process involves taking minute amounts of tissue samples from a
donor that can be broken down into their constituent parts, allowing the
identification of individuals, by comparisons to other none samples.
First developed and used as an
identification technique in 1985 [xvii].
DNA testing underwent further refining until in 1991, a process known as
Polymerase Chain Reaction (PCR) was developed; whereby DNA can be cloned to
produce multiple copies of specific regions of human DNA. These regions can then
be examined to see if they are linked genetically to other individuals.
|
|
Although DNA testing could and
may be able to provide answers to the chronology and genealogy of Egypt's
mummies, DNA has been termed as the "genetic fingerprint" of each
individual, passing genetic information from one generation to the next by
making exact replicas of its self. Therefore, the closer a genetic sequence
match is, the higher the probability that the donors share a common ancestry.
Furthermore, an individual's genetic fingerprint is influenced by ones parents'
genes; each contributing half of their genes to their offspring. Mitochondrial
DNA (mtDNA) is inherited from the mother, whilst Nuclear DNA is derived from
both parents and is much harder to obtain for study. |
However, DNA testing is not
without its limitations and is not the panacea as is often widely believed.
 |
 |
|
DNA
Replicated. This shows DNA samples decoded into its polymerase chain
reaction (PCR) identity. |
By
comparing a test sample E (vs) (shown bottom) against donor samples, it
is evident that there is a match with the sample labelled S2. |
[xvii] Encarta encyclopaedia 2004
The limitations of DNA
|
One of the problems of trying to harvest ancient
DNA is that it is one of the first things to undergo decomposition,
breaking the strands of DNA into fragments, resulting in the danger of
false sequencing. |
|
However, far and away the
biggest threat in using DNA is the fear of cross contamination. If a
single modern cell contaminates the sample under analysis, it becomes
worthless. Therefore, it is imperative that any samples harvested are
carried out under the most practically stringent conditions possible. |
|
Through the advent of experimentation, it has been
found that teeth are the best source of harvesting "clean"
DNA. The outer layer is vigorously cleaned, then the tooth is drilled to
gain access to the inner un-contaminated pulp, which is then pulverised
and used for DNA testing. |
|
Since mtDNA is
maternally inherited, one obvious limitation is in an instance when a
mother bears no daughters. Her mtDNA effectively comes to a screeching
halt. Later generations will not have a trace of the former generation's
mtDNA in this case. |
|
Autosomal (nuclear) DNA is inherited from both a
mother and father (50/50), which makes it more reliable to track, as it
recombines. In addition to certain mtDNA becoming extinct due to
the lack of daughters, we must also consider new mtDNA showing up
due to new groups being introduced to a given population. This can also
significantly skew any results. |
|
Moreover, the difficulty in
harvesting the father’s DNA to prove paternity, limits the value of
genetic testing. Dr Hawass of the SCA has always been sceptical of using
DNA citing "From what I understand, it is not always accurate and
it cannot always be done with complete success when dealing with
mummies. Until we know for sure that it is accurate, we will not use it
in our research" [xviii]. |
|
| [xviii] Interview with al-Ahram
issue 512 |
Using DNA
| Back in 1993-94 Professor Scott Woodward,
a microbiologist from Brigham Young University (USA) was asked to
demonstrate the usefulness of DNA, testing on six mummies from the Old
Kingdom period, with the aim of providing clues to their sexing and
possible genealogies.
Woodward was able to determine that two of the mummies had been
[accidentally?] placed inside the wrong coffins.
Following his success, Woodward was invited to the Cairo Museum
sometime during the mid 90’s to examine and harvest tissue samples from
27 royal mummies from the New Kingdom Period, during their removal to a
new display room. |
|
From the 27 mummies, only 7 yielded successful
DNA sequences. However, from his results he was able to determine that
Ahmose I had married his full sister Seknet-re and that
Amenhotep I's
mtDNA was different from Ahmose I, making it highly likely that Ahmose –
Nefertari was in actual fact Amenhotep I's mother.
Furthermore, according to his DNA evidence, it is highly probable that
Amenhotep I was Thutmosis I's father, which opposes conventional wisdom,
stating that the 18th dynasty revealed "a very narrow gene pool"
[xix].
However Woodward does agree with Wente and Harris on the identity of
Thutmose III stating "Thutmose III is identified with a high degree
of certainty". |
|
|
|
|
The "Holy Grail" of DNA testing, would without a doubt be the
comparison between Tutankhamun, Amenhotep III and Akhenaten's DNA sequences.
This dream almost became a reality on December 12th, 2000, when a joint team
from Waseda University in Japan and Cairo's Ein Shams University were given
permission to take tissue samples.
Unfortunately, the Egyptian Government withdrew permission at the last moment.
The SCA rejected the request on the grounds that it represented a threat to the
mummy's fragile condition and would, in any case, prove futile.
Hawass again said DNA analysis was
out of the question because it would not lead to anything
[xx].
Then in 2003, Woodward was approached and given permission by the Egyptian
government to harvest tissue samples from Tutankhamun. But once again, the
Egyptian Government rescinded, citing reasons of "national
security".
|
|
Hassan Bassiouni, a genetic researcher at Al-Azhar University, argued that it
might prove impossible to establish Tut's lineage by examining the DNA samples
because all cells had died many years ago and that they were probably contaminated by
liquids and materials used in mummification, as well as natural erosion factors.
Nasry Iskander, an Egyptian scientist who has done extensive work on mummies,
says Tutankhamun's mummy was in too poor a condition for X-rays to yield any
conclusive answers.
He says that in the future, DNA analysis of tissue material might help solve
the mystery [xxi].
However, the Egyptian Government did grant permission for Woodward to
harvest and sequence mtDNA and Nuclear DNA from Tutankhamun's eldest foetus
[xxii]
– to date, the results have not been published.
|
In conclusion, it is apparent that no
single individual system for determining a definitive chronology works. But, by
combining all the known scientific fields together, including the newest member,
CT scanning, perhaps and only then, will the fields of science and Egyptology be
able to finally unravel the mystery of the mummies.
|
Note: At the time of writing this article (Jan
2005), the SCA took a momentous decision and had the body of Tutankhamun
removed from his tomb, in order for it to be CT scanned. It is believed that a
DNA sample would be taken, whilst given the opportunity. It is hoped from the
results, to finally prove whether the boy king was murdered and with the DNA
samples determine his lineage. See
the results here >>
|
|
|
| |
References for this page: |
| [xix] |
Secrets of the Ancient World revealed
through DNA. 2001, S Woodward. |
| [xx] |
Interview with "Travel Egypt"
magazine, 2004. |
| [xxi] |
Internview with Mark Rose, editor of
"Archaeology", March 2003. |
| [xxii] |
http://molecular-geneaology.byu.edu/group.html |
return to the main articles page
>> |
|
|
