Figure 2

The haplogroup classification tree of 61 complete mtDNA sequences (a, b). The nucleotide positions in the sequences were scored relative to the reference sequence NC_007235 which is noted by the dashes. Transitions are shown on the branches and transversions are further annotated by adding suffixes. Deletions and insertions are indicated by ‘d’ and ‘+’, respectively. Amino-acid replacements are in red and marked by a single-letter code, whereas synonymous replacements are in blue. Changes in ribosomal RNA genes are denoted by ‘r’. The exclamation mark ‘!’ designates back mutation and recurrent variants are underlined. ‘R’ and ‘Y’ specify the heteroplasmic status of A/G and C/T at a certain site, respectively. All heteroplasmic variants are excluded in the analyses and are marked in italics. ‘0’ represents the previous reference sequence NC_001323 which was excluded in subsequent analyses because of potential sequence errors. Labels of sequences are in accordance with Figure 1. (c) The geographic origin of samples as shown by different colors.