Figure 1
From: Maternal-offspring conflict leads to the evolution of dominant zygotic sex determination
Maternal and zygotic optimal sex ratios in relationship to relative cost of male production (β). When β < 0, males reduce brood fitness more than daughters, and a female-biased sex ratio is favoured for both maternal and zygotic genes. Similarly, when daughters are the more detrimental sex (β > 0), a male-biased sex ratio is selected. Maternally-expressed genes favour a more skewed sex ratio (solid line) than zygotic genes. The zygotic optimum depends on relatedness within broods: genes expressed in full-sibships (crossed line) are selected to bias the sex ratio more than genes in half-sibships (dashed line).
