North Mississippi Allstars, scheduled for three area gigs this week (a free in-store appearance 4 p.m. Thursday, July 20, at Twist & Shout, plus full-sized shows July 20 at the Gothic Theatre and Friday, July 21, at the Fox Theatre), are a different kind of second-generation band; key members Luther and Cody Dickinson are the sons of a famous producer (Jim Dickinson), not a famous musician. But whereas their dad is best known for working with acts such as the Replacements and Beck, guitarist Luther and drummer Cody, assisted by bassist Chris Chew, do the roots-blues thang on Shake Hands With Shorty, their debut for Boston’s Tone-Cool imprint. While they’re clearly influenced by modern blues primitives such as R.L. Burnside -- two of Burnside’s sons, Cedric and Garry, guest on the disc -- they aren’t nearly that down and dirty. Their singing is on par with yours and mine (in my case, at least, that’s not a compliment), and on the wanky All Night Long,: Luther’s soloing is more reminiscent of Trey Anastasio’s on a bland day than Howlin’ Wolf’s on a happenin’ one. However, tracks such as Shake ’em on Down,: Skinny Woman: and Drinkin’ Muddy Water: are pleasantly gritty, and the boys’ enthusiasm usually makes up for a certain lack of authenticity. In the end, Shorty’s a pretty decent argument for nepotism. Relatively speaking, that is.