Abstract Background Allotetraploid F1 hybrids (4nF1) (AABB, 4n = 148) were generated from the distant hybridization of Carassius auratus red var. (RCC) (AA, 2n = 100) (♀) × Megalobrama amblycephala (BSB) (BB, 2n = 48) (♂). It has been reported that Hox gene clusters are highly conserved among plants and vertebrates. In this study, we investigated the genomic organization of Hox gene clusters in the allotetraploid F1 hybrids and their parents to investigate the polyploidization process. Results There were three copies of Hox genes in the 4nF1 hybrids, two copies in RCC and one copy in BSB. In addition, obvious variation and pseudogenization were observed in some Hox genes from 4nF1. Conclusion Our results reveal the influence of polyploidization on the organization and evolution of Hox gene clusters in fish and also clarify some aspects of vertebrate genome evolution.
