REPORT An African American Paternal Lineage Adds an Extremely Ancient Root to the

ca s c en s e m im s ov tio in h Y454 The American Journal of Human Genetics 92, 454–459, MarchGenotyping of a DNA sample that was submitted to a commercial genetic-testing facility demonstrated that the Y chromosome of this African American individual carried the ancestral state of all known Y chromosome SNPs. To further characterize this lineage, which we dubbed A00 (see Figure S1, available online, for proposed nomenclature), we sequenced multiple regions (totaling ~240 kb) of the X-degenerate portion of this chromosome, as well as a subset of these regions (~180 kb) on a chromo-some belonging to the previously known basal lineage A1b (which we rename here as A0). We note that all sampling procedures described herein were approved by and per-formed according to the ethical standards of the University of Arizona Human Subjects Committee. The ancestral state for the Y chromosome, L is the length of sequence analyzed for the autosomes, T is the average number of new mutations per genome in the autosomes, g is the generation time, b is the increment in mutation rate per base per year increment in the paternal age, F is the number of mutations originating in the mother, and g0 is the average age of fathers in the study, 14 then L$mY T=g þ bð1 g0=gÞ F=g. We obtained median values and generated 90 % confidence intervals (CIs) for mY as a function of g (ranging from 20 to 40 years) by sampling 100,000 times from normal distributions for each of the parameters T ~ N (63.2 [SD 0.9]), b ~