 On November 16, 2015, in a study published in the journal "Nature Communications", geneticists announced that they had found a new fourth ancestral "tribe" or "strand" which had contributed to the modern European gene pool.They analysed genomes from two hunter-gatherers from Georgia which were 13,300 and 9,700 years old, and found that these Caucasus hunter-gatherers were probably the source of the farmer-like DNA in the Yamna.According to co-author Dr Andrea Manica of the University of Cambridge