Schematic of the Population Model Used

<p>The Neanderthals contribute a proportion <i>p</i> to the ancestry of CEU individuals <i>t</i>_a generations in the past, where <i>t</i>_a = 1,800 (see Noonan et al. [<a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.0030175#pgen-0030175-b001" target="_blank">1</a>]). <i>T</i>_s is the split time of the two populations. The red lines show the ancestry of a particular Neanderthal and modern human sequence. They coalesce at time <i>T</i>_MRCA in the past.