DNA harvested from the remains of an infant buried 13,000 years ago confirms that the earliest widespread culture in North America was descended from humans who crossed over to the New World from Asia, scientists say.

The research, detailed in this week's issue of the journal Nature, also suggests that many contemporary Native Americans are direct descendants of the so-called Clovis people, whose distinctive stone tools have been found scattered across North America and Mexico.

The origins and genetic legacy of the people who made Clovis tools have been topics of debate among scientists. While most archaeologists think that the Clovis people were descended from Asians, an alternative theory suggests that the Clovis ancestors emigrated from southwestern Europe during the Last