Relationship between genome size and length of the portion HoxA4 to HoxA9 of HoxA clusters. The length of HoxA clusters is correlated (P = 0.06) with genome size expressed as C value. The HoxAα cluster lengths are shown. To be able to include also striped bass (HoxA cluster sequence is available only from HoxA4α to HoxA10α) and zebrafish (HoxAα cluster lacks HoxA10α) into the analysis, only the length of the HoxA4 to HoxA9 portion of the cluster is shown.