Figure 8.

Genes at or near the sex determining region are differentially expressed by gender. (A) Direction of differential expression (top panel – male biased or bottom panel - female biased) is strongly dependent on the spatial organization of the genes (see Table 4). This heat map includes genes from chromosome 18 and unassigned contig scaffold 42 (the sex determining region is actually on chromosome 19 but it is misassembled in v.3 of the Populus trichocarpa genome⁵). Genes with significant differential regulation are detailed in Table 4. (B) Expression of putative sex determining (ferminizing factor) gene ARR17 (gene with female-specific expression assembled to chromosome 19, see text.) The strongest sex-differential expression is at the earliest stage. The y-axis represents expression intensity as log cpms (counts per million). Sample labels: F/M represents female or male; numbers correspond to months. E.g. F06 corresponds to female buds harvested in June.