As with any communal project, the nomenclature of biology can get kind of quirky. The Curiosities of Nomenclature site is dedicated to fishing out some interesting ones.
My favorite Russian Doll nomenclature has always been the Drosophila series of mutations, sevenless, son of sevenless (sos), and bride of sevenless (boss), all of which are genes important for eye development. Sevenless mice are missing neuron number 7 in the small repeating arrays known as ommatidia. Sos was later identified in mouse and became m-sos; but then there are two variants, m-sos1 and m-sos2. More cool names from this family, including many allusions to German foods, are at FlyBase .