What are "duelling banjos"?

I read this phrase recently in the context of a complex, intense and possibly racially-charged dispute among a group with labyrinthine and possibly incestuous interrelationships. The complete sentence was "What's the Rotherham equivalent of duelling banjos?"

"Duelling Banjos" is the name of an instrumental breakdown - actually, a "duel" between a guitar and a banjo. It was featured prominently in "Deliverance", a classic American movie about a group of big-city friends who go on a hunting trip into deepest Appalachia - an area rife with "labyrinthine and possibly incestuous interrelationships".

The song has woven itself into American culture so deeply that, at least among my acquaintances, all you have to do is cradle your arms as if holding a banjo, make a picking motion with your right hand, and say "bing bing bing bing bing bing bing" (imitating the first few notes) and it is immediately understood that you are referring to... um... "genetically deficient" individuals. Robin Williams has often used this bit of shorthand in his stand-up comedy (2:50 or so), for instance.

Dueling Banjos is the title of a 1955 instrumental composition. (Wikipedia article). It features two banjo parts echoing and competing against each other.

"Dueling Banjos" was used in the movie Deliverance, in which some of the inhabitants were implied to be inbred.

Rotherham is a small town in South Yorkshire, England. However, Rotherham is a very conservative town. You could be fined for swearing..

I can't really answer it better than with a video—well, an audio. It's a popular banjo tune. What the Rotherham equivalent of that is I have no idea...is it referring to the city in Yorkshire? Rotherham FC?