A team of scientists in the UK recently confirmed that skeletal remains discovered beneath a parking lot in Leicester belong to King Richard III. Richard Buckley, lead archaeologist from the University of Leicester, asserts this is "beyond reasonable doubt," based on genetic and historical forensic evidence.
However, some skepticism regarding the DNA evidence is "entirely appropriate," says Dr. Timothy Bestor, Professor of Genetics and Development at Columbia University Medical Center. The DNA tests involve comparing 300 nucleotide-long regions of mitochondrial DNA (mtDNA) between the excavated bone samples and living descendents of King Richard III's sister. Because the mitochondrial genome is transmitted exclusively from mother to offspring, with no paternal input, matrilineal patterns of descent can normally be distinguished based on comparisons of mtDNA control regions. (This post from the Human Genome Project explains how genetic markers—specific sections in the genetic code that vary between people—can be used in identification.) In this case, cautions Dr. Bestor, there are four particularly complicating factors.
The first is the quality of the DNA samples. After 500 years or more in a wet environment like England's, "the microbes are going to degrade the DNA. It’s just food to them," says Dr. Bestor. The risk of sample contamination is also high.
Secondly, the English aristocracy reproduced within a closed gene pool in order to preserve lineages. This inbreeding results in consanguinity. Because of this, Dr. Bestor stresses, "you may have the same mitochondrial haplotype, but that does not guarantee a lineal descent from a given individual."
Another confounding factor is that, in the 17-25 generations separating King Richard III’s sister from her extant relatives, there is a fair chance that children of deceased parents may have been adopted by their parents’ siblings somewhere along the way. After all, medieval life expectancies were short. Such adoptions may have been kept private and excluded from historical genealogical records.
Dr. Bestor also points out that the genetic sequences and statistical data are yet to be released. However, he adds more optimistically, "the historical evidence is quite compelling."
Forensic examination of the bones showed they belonged to a slender, adult male with scoliosis in his 20s or 30s. King Richard III was killed at the age of 32 and described as "hunchbacked." Furthermore, carbon dating indicates the bones date to 1455-1540, consistent with King Richard III's death in 1485. Traces of battle injuries were also found on the bones, "one likely inflicted from behind by an assailant bearing a halberd, a medieval weapon consisting of an axe blade topped with a spike," according to this National Geographic article.
The announcement that King Richard III—famously vilified in the eponymous Shakespeare play—had been found and identified has prompted a flurry of debate about historical assumptions, as well as a new territorial battle over the sovereign's final resting place.