The remains of a neanderthal woman, found in a cave in Siberia in 2010, is unlocking secrets of our lineage and the interbreeding that contributed to modern humans' DNA makeup.
The remains of the woman found in a cave in Siberia in 2010 have given scientists high quality samples to study and .
The LiveScience website says the woman's toe bone - which is at believed to be least 50,000 years old - was sequenced, revealing that both inbreeding and breeding between human lineages.
Modern humans are the only surviving lineage but neanderthals and the more recently discovered denisovans also roamed the earth.
Their lines diverged from the line that became today's man.
Neanderthals lived with homo sapiens for a time, until they died out about 30,000 years ago, and we arguably went on to rule the world.
Denisovans were first discovered in Denisova cave in Siberia in 2008 and in 2010 anthropologists doing further research found the woman's toe bone in the cave.
"The investigators completely sequenced the fossil's nuclear DNA, with each position (or nucleotide) sequenced an average of 50 times. This makes the sequence's quality at least as high as that of genomes sequenced from present-day people," LiveScience said.
The studies on the toe show that neanderthals looked near and far for lovemates.
The neanderthal woman's parents were closely related - possible grandparent and grandchild or half siblings but neanderthals also interbred with both denisovans and homo sapiens.
USA Today says a fourth lineage also pops up in the research results.
"Most striking of all, the analysis found that Denisovans mated every so often with an archaic human that had arisen a million or more years earlier," USA Today says of the research.
"The most likely candidate, the researchers say, is Homo erectus, an early human that began to spread out of Africa roughly 2 million years ago – many hundreds of thousands of years before Denisovans began to emerge as a separate branch of the human family tree."