Fig. 1.

Drift in heteroplasmy frequency estimated for different stages of ontogenetic development with the BLS (A and B) and OPL (C and D) approaches. (A) Assumed phylogeny for an example 1-mother–2-children family showing branch lengths that can be estimated in the BLS framework. Branches (bl = blood, ch = cheek, child 1 = older child, child 2 = younger child) are not drawn to scale. (B) BLS-estimated distribution of mean lengths (in drift units on the x axis) for each branch in the phylogeny (y axis). The colors correspond to branches in A. (C) Ontogenetic phylogeny assumed under the OPL model for the same 1-mother–2-children pedigree as in A. Each solid branch represents an ontogenetic process assumed to impart the same amount of genetic drift and mutation in every individual. Each dashed line represents an ontogenetic process in which genetic drift and mutation are assumed to accumulate linearly from birth until sampling or childbirth. Branches are not drawn to scale. (D) OPL-estimated posterior distribution of genetic drift and mutation rates. The latter are scaled by an effective population size N_e for different ontogenetic processes. The colors correspond to processes in C.