214 Chapter 6
Figure 6.7 The evolution of the bglobin gene cluster. Transcription orientation is indicated by arrows. Exons are
shaded. a: an a globin-like gene. b: a bglobin-like gene. Diagonal lines in the amphibian cluster indicate
a longer distance between the genes. c: pseudogene
Figure 6.6 The silkmoth chorion multi-gene family: a 2-gene unit, where each gene is transcribed in the opposite
orientation and which has been amplified multiple times. Shadings indicate sequence divergence that
has occurred following amplification