[Mr. Jelly]

I love the sound of mandolin especially playing the blues. Though I haven't heard much of bit. (Suggestions?) I am mandolin ignorant so bear with me if this is an ignorant question. What's the explanation about mandolins playing in the key of E? I play a fair amount of blues in E and I am wondering how uncommon and/or difficult is it for a mandolin player to play in E. I know they like G and D. Could they detune or get a bigger mandolin and detune? Whatever. I don't want to capo the guitar to G so there is no need for that discussion. Thanks