1. Parent of Origin, Mosaicism, and Recurrence Risk: Probabilistic Modeling Explains the Broken Symmetry of Transmission Genetics 
Ian M. Campbell, Jonathan R. Stewart, Regis A. James, James R. Lupski, Paweł Stankiewicz, Peter Olofsson, Chad A. Shaw 
The American Journal of Human Genetics 
Volume 95, Issue 4, Pages (October 2014)
DOI: /j.ajhg
Copyright © 2014 The American Society of Human Genetics Terms and Conditions

2. Figure 1
Stochastic-Process Model of Sexual Dimorphisms during Gametogenesis
Phase 1: both males and females experience a stochastic exponential cell-expansion phase modeling embryogenesis and germ cell proliferation. Mutations can arise in any cell division, and if they persist in the clonal lineage, they could ultimately be available to be transmitted to the next generation.
Phase 2: in males, expansion is followed by a stochastic but nonexpanding self-renewal process modeling spermatogenesis.
Phase 3: a single sperm and egg are randomly sampled after meiosis to fertilize an offspring. Adapted from Campbell et al.4 with permission.
The American Journal of Human Genetics  , DOI: ( /j.ajhg )
Copyright © 2014 The American Society of Human Genetics Terms and Conditions

3. Figure 2
Analysis of the Mean and Variance of the Unconditional Proportion of Mutant Gametes
(A) Unconditional on the observation of an affected offspring, the mean proportion of mutant sperm and the expected risk of a first affected offspring (the sum of sperm and egg) are presented over various possible paternal ages according to our model. Mutation risk increases with paternal age.
(B) Coefficient of variation of the proportion of mutant sperm as a function of paternal age. Notably, the curve sharply decreases, indicating that although the proportion of mutant gametes increases, the variability among fathers of a given age decreases in relation to the mean. For these analyses, we set λ1 = λ2 = 1 × 10−10, p = q = 0.9, α = 0.05, β = 0.05, γ = 0.05, and ξ = 0.05 (see Material and Methods). An interactive version of this analysis is available online.
The American Journal of Human Genetics  , DOI: ( /j.ajhg )
Copyright © 2014 The American Society of Human Genetics Terms and Conditions

4. Figure 3
Analysis of Recurrence Risk as a Function of Parent of Origin and Paternal Age
Because oogenesis completes during embryogenesis, recurrence risk of maternally transmitted mutations is not expected to vary with maternal age. According to our model, recurrence risk of paternally transmitted mutations steadily decreases with age, despite an increasing risk of a first affected offspring. When the parent of origin is unknown, the overall recurrence risk is the probability-weighted sum of the recurrence risks for both parents. An interactive version of this analysis is available online.
The American Journal of Human Genetics  , DOI: ( /j.ajhg )
Copyright © 2014 The American Society of Human Genetics Terms and Conditions