Fig. 4

a Heat map and cluster dendogram showing differential gene expression between male and female kiwi. Green and red indicate low and high expression, respectively; data are normalized per gene and sample. Mean male-biased (94 genes) and female-biased (56 genes) expression was 2 and 11 fold and ranged from 1 to 101. Sixty-four of 66 genes showing male-biased expression mapped to chicken chrZ (b) Distribution of male to female expression ratio (b) and SNP density (c) across the mapping position of chicken chrZ, including genes with significant male-biased expression (black circles) and genes equally expressed between sexes (open circles). Lines represent a moving average across ten genes; yellow shading indicates chromosomal regions with both male-biased expression and SNP density and so likely outside the PAR