Tuesday, December 2, 2014

Royal Bones Found in Parking Lot

Two years ago an old skeleton was found under a parking lot in Leicester England. The archaeologists who found the skeleton claimed they found the bones of Richard III, a 15th century monarch. This claim was based on the fact that the skeleton was male, the right age, had battle injuries, and scoliosis. The scientists couldn't be entirely sure it was him so of course DNA evidence was needed.
Image from http://www.thetimes.co.uk/tto/multimedia/archive/00380/RichardIII_380709a.jpg
Today, December 2nd, it was announced that the DNA analysis of the skeleton was completed. It was reported in Nature Communications. The DNA analysis proved that they bones did belong to the former king. The scientists were able to trace the genetic evidence through more than 20 generations of the dead King's family tree to his living descendants. This means that the oldest DNA identification case of known individual was completed.  Turi King, the lead geneticist who lead the analysis stated that they were even 99.999% sure that the remains belong to Richard III.
What the team did was scrape together a DNA profile from a very old skeleton. Since the DNA was so old and damaged, scientists had to look through millions of ribbons of splintered DNA strings. Also to make sure the analysis wasn't contaminated, scientists did the sequencing in multiple clean rooms at multiple locations. Then the profile was compared to Richard III's living relatives. That was still difficult though because an ancestor from 20 generations back would only contribute .000001 of an individual's DNA. What does go almost unchanged through generations is mitochondrial DNA and the DNA on the Y chromosome. Mitochondrial DNA only comes from the mother allowing scientists to look at an all female line through the family tree. It was discovered that the descendants had the exact same mitochondrial DNA except for 1 single mutation. Richard did not have a pure male-line descendants making the tracking of the Y chromosome difficult. The team had more than enough information though.
I thought this was extremely interesting and relevant to class because we were looking at case studies similar to this with mummies and learning about how difficult it is to extract DNA from the dead and how there is a great risk of contamination. It is amazing what can be done with information on someone's DNA.

Article: http://www.popularmechanics.com/science/health/genetics/scientists-confirm-remains-king-richard-iii-17487010

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