Cloning is still not an exact science. Mutation is still a factor when trying to perfectly replicate creatures. That's bad for human cloning, when it results in babies with fingers growing out of their toes. But it's good for music: No matter how faithfully a band tries to re-create a sound, it will end up with something original.
It would be unfair to label Manda & the Marbles a Go-Go's clone: For one thing, two of the members are dudes, so obviously some mutation is going on here. But the egg of the band definitely had some of Belinda Carlisle's DNA injected into it. How else to explain the hooky vocals of Manda (no last name required), who sounds like Belinda in her gorgeous heyday?
Another, more recent relative of the band would be the Donnas, who hit it big recently with their Joan Jett gene carrying retro rock. While tons of other bands are depleting the garage-rock gene pool as quickly as they can, these female-fronted bands get to explore a whole other branch of rock. The Marbles' hooks are sweeter and catchier than their male-fronted counterparts' machismo allows, and it's nice to see a pop-rock band leave the '60s out of their system. It might not be evolution, but it's a start.