We investigated the incidence of the Region V mitochondrial,a DNA 9-base-pa
ir (bp) deletion from human remains recovered from several archaeological s
ites and contexts throughout Argentina. Of the 34 samples analyzed, 24 yiel
ded DNA extractions that gave clear amplification results. All of the indiv
iduals carried two repeats of the 9 bp, one of which has been shown to be d
eleted in some individuals of Asian origin and defines mitochondrial lineag
e B. Although most of the modem Amerindian groups in the region exhibit the
deletion in high frequencies, the absence of the 9-bp deletion among ancie
nt populations of South America seems to be the rule rather than the except
ion, as was reported by several studies involving extinct populations. The
evidence gathered until now suggests that the earliest settlers of this reg
ion of South America did not carry mitochondrial lineage B.