== Better research and citations == 

 The article is working, it seems, from some rather dated material on Beringia.  In: 
 *Bonatto SL, Salzano FM.  1997.  A single and early migration for the peopling of the Americas supported by mitochondrial DNA sequence data. Proc. Nat. Acad. Sci. 94(5): 1866-1871. 
 They indicate that migration could have been occuring as early as 55,000 ybp. 

 In addition, differing information has come from the comparison of mtDNA haplotypes and Y-chromosomal haplotypes.  Compare:  
 *Silva Jr. W , Bonatto S , Holanda A , Ribeiro-dos-Santos A , Paixão B , Goldman G , Abe-Sandes K, Rodriguez-Delfin L, Barbosa M, Paçó-Larson M, Petzl-Erler M, Valente V, Santos S , Zago M .  2002. Mitochondrial Genome Diversity of Native Americans Supports a Single Early Entry of Founder Populations into America. Am J Hum Genet. 71(1): 187-192. 
 and 
 *Lell J , Sukernik R , Starikovskaya Y , Su B, Jin L, Schurr T , Underhill P , Wallace D.  2002.  The Dual Origin and Siberian Affinities of Native American Y Chromosomes. Am J Hum Genet.  70'(1): 192-206.