Proportion of excess sequencing. (A) Curves show the proportion of excess sequencing, R(d,θ) as a function of mean initial ocean size θ for various library depthsd = 10, 15, 25, 50, and ∞. (B) Curves show the proportion of excess sequencing attributable to inefficient ocean closure, R*(d,θ). This is obtained by subtracting the proportion of excess sequencing for an optimal tiling path in a library of depth d, which is 1 / (d − 1). That is,R*(d,θ) = R(d,θ) − (1 / d − 1).