Is GoChain on Ethereum?

Excuse me, could you please clarify for me whether GoChain is actually built on top of the Ethereum blockchain? I've heard conflicting information and I'm trying to get a definitive answer. If GoChain is indeed a sidechain or an extension of Ethereum, could you elaborate on how they're connected and what are the benefits of this arrangement? On the other hand, if GoChain operates independently from Ethereum, what are the key differences between the two platforms and why would someone choose one over the other? I'm really interested in understanding the technical details behind this question.