The modern tiger (Panthera tigris) is believed to have originated from East and Southeast Asia about two million years ago. This correlates with the family tree of the current study which shows the South China tiger is the oldest subspecies. The first subspecies to be given a scientific name was the Indian tiger or Bengal tiger. The Caspian tiger was the second.

Till now it was believed that during the ice age the tiger migrated north to Siberia from China and then west towards the Caspian Sea. The new family tree refutes the old theory: the tiger went from China to the Caspian region via the silk route and then towards Siberia.

Traditionally eight subspecies of tigers have been recognized based on physical characteristics such as size, fur colour, stripes and geographical location.

However, this classification has been questioned because physical characteristics like colour and size are subjective and do not always reflect genetic differences.