File:Morgan crossover 2.jpg

An illustration of double crossing over, from Thomas Hunt Morgan's A Critique of the Theory of Evolution (1916).

Attribution-Share Alike 2.0 Generic license. Attribution: Beneath crossover Bridge 29 on Macclesfield Canal by Chris Morgan You are free: to share –

Commons Attribution-Share Alike 2.0 Generic license. Attribution: Gas works Lock 16 and crossover bridge by Chris Morgan You are free: to share – to copy

Commons Attribution-Share Alike 2.0 Generic license. Attribution: Crossover bridge near Hyde, Peak Forest Canal by Chris Morgan You are free: to share – to

Attribution-Share Alike 2.0 Generic license. Attribution: A57 crossing Peak Forest Canal at Hyde and canal crossover bridge by Chris Morgan You are free: to