http://news.discovery.com/human/genetics-neanderthal-110718.html
A good discussion on the latest on the theory that Homo sapiens and their neanderthal cousins were well acquainted.
AND
http://www.imamu.edu.sa/DContent/IT_Topics/java/5006ra1.pdf
Worth a read…a good summary on the theories on the complicated relationship between our species and our last hominid cousins.