Figure 2
Molecular clock and exon-intron structure of cephalopod haemocyanin. Relaxed molecular clock with a mean evolutionary rate of 7.636 × 10-4 calculated with BEAST v1.5.4 based on a maximum likelihood tree for the amino acid sequences of the complete haemocyanin molecules of Sepia officinalis (SoH1-SoH3), Enteroctopus dofleini (OdHA, OdHG), Nautilus pompilius (NpH) and Haliotis tuberculata (HtH1, HtH2). The split of gastropoda and cephalopoda about 550 ± 50 Mya was used as calibration point. Included are the exon-intron structures of the haemocyanin of N. pompilius, E. dofleini and S. officinalis. Grey bars indicate the 95% HPD (highest posterior density), i.e. the Bayesian confidence interval of the estimated age.