The effects of expression level (A), expression evenness (B) and chromosomal location (C) on K
asymmetry of paralogous pairs in D. melanogaster, for which expression data are available . Vertical bars are standard errors. Regression lines are drawn based on all data points. A: regression coefficient = 0.397, P < 0.0004. B: regression coefficient = −0.0995, P < 0.11. C: mean log-transformed Ka asymmetry in paralogs located on different chromosomal arms, same arms but over 5 kb apart, less than 5 kb apart in collinear orientation and less than 5 kb apart in inverted orientation. Categories labelled with different letters are significantly different by Tukey test (P < 0.05).