Over 150 years after the Queen of England began her reign over India, the "crown jewel" in a British empire that has since dissolved, a monarch of partial Indian descent is about to sit on the British throne. Prince William, according to a study by a genetics firm called BritainsDNA, likely carries a small amount of Indian DNA.

Here's how that happened. Sometime in the early 1800s, before the British Raj was first established, a Scottish merchant named Theodore Forbes, who worked for the East India Company in the port city of Surat, had a child with his housekeeper, a woman named Eliza Newark. Newark is thought to have been Armenian-Indian. She and Forbes named the child Katherine. Two centuries later, one of Katherine's descendants, Diana Spencer, married the prince of Wales. Their child is Prince William, who is slated to become king.

Researchers say they can't know with absolute certainty that William carries DNA of Indian origin but they believe it's pretty likely. How? His lineage from Eliza Newark is not in doubt; the scientists had to demonstrate (1) that he carries DNA directly from Newark; (2) that this DNA is of Indian origin.

The trick is something called mitochondrial DNA, which passes largely unchanged from a mother to her children. Newark and William, as it happens, are connected through a purely maternal line: Newark's daughter had a daughter who had a daughter who had a daughter who had a daughter who had a daughter, Princess Diana, who had William. That means the mitochondrial DNA had a good chance of surviving down the line.

Here's Sky News's summary of how researchers used this connection, as well as previous research that maps certain DNA markers to geographic origins, to find that Newark's direct descendants have about one half of one percent Indian DNA:

Using birth, marriage and death records, he said researchers traced two of Eliza's living direct descendants, who are both third cousins of Princess Diana's mother, Frances Shand Kydd, and tested samples of their saliva.
Using other genetic tests to corroborate the findings, they also discovered that the two direct descendants were around 0.3% and 0.8% South Asian. The rest of their DNA was of European origin.
"This was independent evidence that there was Indian ancestry," said Dr Wilson.
"For me, it corroborated the findings from the mtDNA. We've got two different kinds of genetic evidence that are independent from one another and they both corroborate the story. So it really seems that our future king has a little bit of Indian blood."

So there you have it: Two centuries after British merchants and generals began colonizing India and half a century after the country won its freedom, India has now sent one of its own to reverse-colonize the United Kingdom by taking the English crown, or at least 0.3 to 0.8 percent of it.