How a protein modification navigates sperm to the egg

For fertilisation, millions of sperm cells race toward the egg by rhythmically wagging their tail. How they head to the goal straight is unknown. A new study reveals that a chemical modification on proteins controls the sperm tail’s behaviour, and in its absence, amazingly, sperm turns to swim circularly, rather than to swim straight toward the egg, causing defects in male fertility. - submission by Sudarshan Gadadhar, Carsten Janke