Cryo-Electron Tomography Illuminates A New Structure Inside Human Sperm

Scientists have discovered a new helical nanostructure inside human sperm which they've named TAILS.  The acronym stands for "tail axoneme intralumenal spiral". It's unclear exactly what this structure does, but some hypothesize "that this spiral may act as a cork inside the microtubules, preventing them from growing and shrinking as they would normally do, and instead allowing the sperm's energy to be fully focused on swimming quickly towards the egg." (Read on)