Establishment of a hybrid lineage via Megalobrama amblycephala (♀) × Culter alburnus (♂) and Genetic Analysis

Distant hybridization is a significant method for creating new hybrid lineages and potentially hybrid species. In the past ten years, we have established a hybrid lineage population, BTF 1 -BTF 6 (six generations), via crosses between Megalobrama amblycephala (blunt snout bream, BSB, 2 n = 48, ♀) and Culter alburnus (topmouth culter, TC, 2 n = 48, ♂). The DNA content and the chromosome number showed that the hybrid lineage (BTF 1 -BTF 6 ) was diploid with 48 chromosomes. Furthermore, examining the genomes of BSB and TC, we identified 10 Hox genes from the Hox family that exhibited significant single-nucleotide polymorphisms (SNPs), which we utilized to differentiate between the two parental genomes. Subsequent cloning and analysis of these 10 Hox genes in the hybrid lineage (BTF 1 -BTF 6 ) indicated that most of the heterologous genes stably coexist within the hybrids. However, a small fraction of genes inherited from the male parent may be lost during the establishment of the hybrid lineage. Additionally, chimeric genes were detected in the BTF 1 population, demonstrating stable inheritance within the hybrid lineage. The establishment of this hybrid lineage from female BSB and male TC not only serves as a vital model for investigating genetic variation in early hybrid speciation but is also crucial for advancing fish genetic breeding. • Establishment of a stable diploid hybrid lineage. • Heterologous genes can coexist stably in the hybrid lineage. • Some of the paternal genes are lost in the hybrid lineage. • The chimeric genes were found in the BTF 1 .