Scientists doing genetic studies have thrown doubt on the genuineness of a gruesome relic from France, a gourd purportedly carrying stains made by the blood of the executed King Louis XVI.

Sequencing the genome of the dried blood found inside the 200-year-old relic did not provide any correlation with the king's known DNA signatures.

Those signatures were created by genome sequencing of known descendants in Louis XVI's line.

The blood in the gourd also did not match the genetic code for some celebrated known traits of the king, which included blue eyes and imposing height.

In the journal Nature, the researchers wrote, "We found that the ancestry of the gourd's genome does not seem compatible with Louis XVI's known ancestry."

In the wake of the French Revolution, King Louis XVI lost his head to the guillotine early in 1793. Marie Antoinette, his wife, met a similar fate several months later.

There have long been stories of witnesses using their handkerchiefs to soak up the executed king's blood.

The elaborately inscribed gourd at the center of the mystery carries an inscription claiming one of the bloody handkerchiefs has been stored inside.

It is much more likely, the researchers say, that the gourd was created as a fake souvenir of the revolutionary end of the king in an attempt to make money.

"In the French revolution, the guillotine was working every day -- and probably it was much more easy to approach the scaffold when non-important people were being beheaded," says Carles Lalueza-Fox of the Institute of Evolutionary Biology in Barcelona, Spain.

"Maybe that was one of the occasions. They thought nobody was going to be able recognise whether the blood was from the king or not."

The gourd has been in the possession of a family in Italy for the past hundred years.

The researchers say their investigation marks a first attempt to sequence DNA of someone from the latest period of history.

"This is the first draft genome generated from a person who lived in a recent historical period; however, our results suggest that this sample may not correspond to the alleged king," researchers wrote in Nature.

Scientists have previously sequenced the DNA from individuals who lived during the Ice Age and from individuals of two early groups of humans, the Denisovans and the Neanderthals.