Karyological analysis of Ctenopharyngodon idella, Aristichthys nobilis, and their F1 hybrid

Ctenopharyngodon idella (grass carp) and Aristichthys nobilis (bighead carp) have a diploid chromosome number of 48 with no acrocentric chromosomes. The hybrid of these species is triploid with 72 chromosomes. The frequencies of metacentric and submetacentric chromosomes suggest that the hybrid receives two maternal and one paternal set of chromosomes.