Figure 1.

Event with ploidy r_i = 4, showing population of m_i = 5 genes at time t_i, each giving rise to 4 progeny, of which 1 ≤ j ≤ 4 survive until time t_i+1. $a_j^{(i)}$ is the number of times j progeny survive. Black lines represent individual progeny that survive, and grey lines represent the total progeny of a gene that do not survive. Here, $a_1^{(i)}=2,a_2^{(i)}=a_3^{(i)}=a_4^{(i)}=1$. From [2].