Time-scaled gene tree for 19 biallelic Y-chromosome haplotypes. Each mutational event at one of 18 biallelic sites on the nonrecombining portion of the Y chromosome is represented by a dot (single-nucleotide polymorphism) or a square (small insertion/deletion). Mutational ages (in 103 yr) are indicated on the y axis, and the haplotypes defined by these mutational events are shown on the x axis. 1 = SRY10831.1, 2 = PN3, 3 = RPS4Y711, 4 = YAP, 5 = SRY4064, 6 = PN2, 7 = p(A)L→S, 8 = PN1, 9 = DYS188792, 10 = p12f, 11 = DYS221136, 12 = DYS211105, 13 = M9, 14 = Tat, 15 = DYS257, 16 = DYS194469, 17 = DYS199, 18 = SRY10831.2⋅