Our search for Tutankhamun's mother and wife focused on four unidentified females. Two of these, nicknamed the "Elder Lady" and the "Younger Lady," had been discovered in 1898, unwrapped and casually laid on the floor of a side chamber in the tomb of Amenhotep II (KV35), evidently hidden there by priests after the end of the New Kingdom, around 1000 B.C. The other two anonymous females were from a small tomb (KV21) in the Valley of the Kings. The architecture of this tomb suggests a date in the 18th dynasty, and both mummies hold their left fist against their chest in what is generally interpreted as a queenly pose.
Finally, we would attempt to obtain DNA from the fetuses in Tutankhamun's tomb—not a promising prospect given the extremely poor condition of these mummies. But if we succeeded, we might be able to fill in the missing pieces to a royal puzzle extending over five generations.
To obtain workable samples, the geneticists extracted tissue from several different locations in each mummy, always from deep within the bone, where there was no chance the specimen would be contaminated by the DNA of previous archaeologists—or of the Egyptian priests who had performed the mummification. Extreme care was also taken to avoid any contamination by the researchers themselves. After the samples were extracted, the DNA had to be separated from unwanted substances, including the unguents and resins the priests had used to preserve the bodies. Since the embalming material varied with each mummy, so did the steps needed to purify the DNA. In each case the fragile material could be destroyed at every step.
At the center of the study was Tutankhamun himself. If the extraction and isolation succeeded, his DNA would be captured in a clear liquid solution, ready to be analyzed. To our dismay, however, the initial solutions turned out a murky black. Six months of hard work were required to figure out how to remove the contaminant—some still unidentified product of the mummification process—and obtain a sample ready for amplifying and sequencing.