Map of gene flow in and out of Beringia, according to human mitochondrial DNA haplogroups.
Colors of the arrows correspond to approximate timing of the events and are decoded in the colored time bar. The initial peopling of Beringia (the region depicted in light yellow) was followed by a standstill after which the ancestors of the Native Americans spread swiftly all over the New World while some of the Beringian maternal lineages (C1a) spread westwards. More recent genetic exchange (shown in green) is manifested by back-migration of A2a into Siberia and the spread of D2a into north-eastern America that post-dated the initial peopling of the New World.
Erika Tamm et al
CC BY 2.5
Tamm E, Kivisild T, Reidla M, Metspalu M, Smith DG, et al. (2007) Beringian Standstill and Spread of Native American Founders. PLoS ONE 2(9): e829. <a href="//doi.org/10.1371/journal.pone.0000829" class="extiw" title="doi:10.1371/journal.pone.0000829">doi:10.1371/journal.pone.0000829</a>. Also available <a rel="nofollow" class="external text" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1952074&amp;rendertype=figure&amp;id=pone-0000829-g002">from PubMed Central</a>.