Ever since the TV show Who Do You Think You Are? began in the UK, USA, Canada, Australia and elsewhere, there has been a growing interest in the roots of the rich and famous. Sometimes it has been somehow unsurprising to hear of them related to royalty, or conversely with the humblest of origins. Here’s what we have learned over the last year or so.

Inevitably the 2012 US Presidential Election saw a lot of digging into the main candidates’ origins. President Obama’s mixed origins and connections to Ireland have been well explored before, but new discoveries included his mother Stanley Ann Dunham probably being descended from a 17th century African servant in Virginia called John Punch (the first documented slave in American history). On the other hand online genealogy guru Dick Eastman observed that the key word there is ‘probably’: “If you go back enough years, everyone is descended from most everyone.” In genealogy, the pudding is in the proof!

If Obama’s white mother may have black roots, it also turned out that Michelle Obama has white roots: her great-x3-grandmother is believed to have been a slave called Melvinia who was made pregnant in 1859 by Charles Shields, one of her owner’s sons and a descendant of Irish immigrant Andrew Shields.

As for losing presidential candidate Mitt Romney, much was made of his roguish ancestor Miles Park Romney, son of one of the first British Mormons and an early settler of the American west; Miles Park Romney was arrested for polygamy in the 1880s and was described by a newspaper editor at the time as “a mass of putrid pus”!

Sometimes researchers discover that two famous people are related to each other. Film buffs are fond of the game ‘six degrees of Kevin Bacon’ (where they find the shortest path between any actor and Bacon through shared film roles) – it turned out that Kevin Bacon and his wife Kyra Sedgwick are actually cousins (discovered by the US TV show Finding Your Roots) – specifically 10th cousins once removed. They are both also related to Richard Nixon, Jimmy Carter and Marilyn Monroe.

Canadian singers Justin Bieber and Céline Dion turn out to be 10th cousins three times removed, sharing roots among the early settlers of Quebec four centuries ago. Their forebears Jacques Vezina and Marie Boisdon were born in France in 1611 and 1615 respectively.

Two Hollywood actors were found to have connections to famous people of the past. Dan Aykroyd is related to a woman called Tabitha Aykroyd – not famous herself, but she became the surrogate mother to the Brontë sisters in Yorkshire, and was the person responsible for fostering their love of reading. Without her, then, the world would have had neither Jane Eyre nor Ghostbusters!

Meanwhile, George Clooney was found to be ‘half first cousin five times removed’ of Abraham Lincoln, a connection so convoluted that it brings Dick Eastman’s warning above to mind again. More specifically, Lincoln’s mother Nancy Hanks was half-sister to Mary Ann Sparrow, Clooney’s 4x-great-grandmother. Still on the Lincoln theme, Discover Your Ancestors writer Anthony Adolph has been exploring the assassinated president’s roots in Norfolk, England. His great-x6-grandfather Richard Lincoln was born in Hingham in 1622 (and died in Hingham, Massachusetts in 1690) and married four times. A dispute with Edward, a son by his first wife, is believed to have lain behind Edward’s son Samuel emigrating to America. Anthony himself has Norfolk roots connecting him to the Fairfax family, ancestors of Duchess of Cambridge Kate Middleton (whose own connections to Beatrix Potter and Jane Austen we covered last time).

DNA testing sometimes proves connections – as well as the much-discussed proof that a skeleton found in a Leicester car park was that of Richard III, DNA has told us that veteran Scottish actor Tom Conti (his most recent film role was in The Dark Knight Rises) is directly related to Napoleon Bonaparte. The discovery, by the ScotlandsDNA project, was based on the two men sharing a distinctive genetic marker called M34, which has its origins in the Saracens of the medieval Middle East.

Sometimes, however, science and history both draw a blank. One interesting revelation from British secret service files released in 2012 was that silent film star Charlie Chaplin was investigated by MI5 because of US suspicion of alleged links to Communism. They looked into his roots – and couldn’t find any record of his birth (believed to be on 16 April 1889). If the nation’s spies can’t always track down someone’s details, perhaps coming up against brick walls in our own family trees isn’t something to be ashamed of!