Figure 6.

Distribution of d/a values for Affymetrix differentially expressed genes. Distributions of d/a ratios for differentially expressed genes based on Affymetrix microarray data. (A) d/a type I values indicate the hybrid expression levels relative to the low-parent and high-parent levels. The distributions are very similar for the six different hybrids. Hybrid expression patterns center approximately around the mid-parent level with very flat distributions outside of the parental range. (B) d/a type II values indicate the hybrid expression levels relative to the maternal-parent and paternal-parent levels. Again, all six hybrids exhibit similar distributions peaking around mid-parent levels, indicating no maternal or paternal expression biases. (C) The distributions of d/a type II values for the subset of differentially expressed genes that exhibited non-additive hybrid expression profiles. The distributions indicate that the non-additive patterns for most genes are still within the parental range, and are oftentimes observed near the mid-parent (additive) values.