Indigenous peoples of the Americas:

A route through Beringia is seen as more likely than the Solutrean hypothesis. Kashani et al. 2012 state that "The similarities in ages and geographical distributions for C4c and the previously analyzed X2a lineage provide support to the scenario of a dual origin for Paleo-Indians. Taking into account that C4c is deeply rooted in the Asian portion of the mtDNA phylogeny and is indubitably of Asian origin, the finding that C4c and X2a are characterized by parallel genetic histories definitively dismisses the controversial hypothesis of an Atlantic glacial entry route into North America."

Please answer a question about this article. If the question is unanswerable, say "unanswerable". What is C4c deeply rooted in the Asian portion of?
the mtDNA phylogeny