Other breakthroughs include the sequencing of the oldest human DNA yet.

Here's a look at what scientists learned about humanity and human origins this year:

Mystery lineage

Recent analyses of fossil DNA have revealed that modern humans occasionally had sex and produced offspring not only with Neanderthals but also with Denisovans, a relatively newfound lineage whosegenetic signatureapparently extended from Siberia to the Pacific islands of Oceania.

This year, hints began emerging that another mystery human lineage was part of this genetic mix as well. Now, the first high-quality genome sequence from a Neanderthal has confirmed those suspicions.

These findings come from Denisova Cave in southern Siberia, where the first evidence of Denisovans was discovered in 2008. To learn more about the Denisovans, scientists examined DNA from a toe bone unearthed there in 2010.

The researchers found that the fossil belonged to a Neanderthal woman. Her DNA helped refine the human family tree, as it revealed that about 1.5 to 2.1 percent of the DNA of modern people outside Africa is Neanderthal in origin, whereas about 0.2 percent of DNA of mainland Asians and Native Americans is Denisovan in origin.