In this episode from our series exploring 100 ideas in genetics, we explore the discovery of chromosomes - the strands of genetic material within every living cell - take a look at Lyonisation, and solve the case of the missing chromosomes. Genetics Unzipped is written and presented by Kat Arney, and produced by First Create the Media for the Genetics Society - one of the oldest learned societies in the world dedicated to supporting and promoting the research, teaching and application of genetics. Production by Hannah Varrall. Full show notes, music credits and references online at GeneticsUnzipped.com)