THE first inkling of maleness began when parasitic bacteria jumped between cells, dragging their host’s genes with them. And according to the researcher who came up with the controversial idea, the vestiges of this inauspicious beginning persist in the sperm of animals today.
Some time between 2000 million and 700 million years ago, bacteria entered into an uneasy truce with larger cells. These cells were the precursors of complex eukaryotic cells, that eventually evolved into today’s multicellular animals and plants. The bacteria wound up losing around 90 per cent of their genes to the host nucleus and became mitochondria –…
