Table 1. Expected and observed TMRCA for autosomes, X chromosome, and mtDNA, under different Y chromosome TMRCAs.
| Expected TMRCA (kya) | ||||
|---|---|---|---|---|
| Citation | Observed TMRCA (in 1000 ya (kya)) | TMRCAY =209 | TMRCAY =338 | |
| Autosomes | 49 | 796 | 836 | 1352 |
| Chr X | 50 | 741 (±168) | 627 | 1014 |
| 51 | 535 (±119) | |||
| mtDNA | 52 | 204.9 (116.8–295.7) | 209 | 338 |
| 53 | 176.6 (±11.3) | |||
For a given TMRCA on the Y chromosome, the expected TMRCA for the autosomes, X chromosome, and mtDNA can be computed, assuming that the effective population size of the Y is equal to that of the mtDNA, one-third that of the X chromosome, and one-quarter that of the autosomes. The expected TMRCAs are calculated using the TMRCA for the Y (TMRCAY) computed using the low Y chromosome mutation rate derived from an autosomal mutation rate (6.17 × 10−10 mutations/nucleotide/year; TMRCAY =338 000 ya), and using the mutation rate estimated from a Y chromosome pedigree (1.0 × 10−9 mutations/nucleotide/year; TMRCAY =209 000 ya).