Evidence for the evolutionary origin of goldfish derived from the distant crossing of red crucian carp × common carp

Jing Wang,Yun Liu,Jun Xiao,Shaojun Liu,Chun Zhang,Kaikun Luo,Min Tao

doi:10.1186/1471-2156-15-33

Abstract

BackgroundDistant hybridization can generate transgressive hybrid phenotypes that lead to the formation of new populations or species with increased genetic variation. In this study, we produced an experimental hybrid goldfish (EG) by distant crossing of red crucian carp (Carassius auratus) × common carp (Cyprinus carpio) followed by gynogenesis.ResultsWe evaluated the phenotype, ploidy level, gonadal structure, and 5S rDNA of the EG. Diploid EG possessed a high level of genetic variation, which was stably inherited. In particular, the EG combined transgressive phenotypes, including a forked tail and shortened caudal peduncle, traits that are present in common goldfish. The EG and common goldfish share a number of morphological and genetic similarities.ConclusionsUsing the EG, we provide new evidence that goldfish originated from hybridization of red crucian carp × common carp.

Highlights

Distant hybridization can generate transgressive hybrid phenotypes that lead to the formation of new populations or species with increased genetic variation
Comparison of morphological traits among experimental hybrid goldfish (EG), naturally domesticated goldfish (NG), red crucian carp (RCC), and common carp (CC) Compared with RCC and CC, EG possessed several unique phenotypes, including a forked tail, spherical body, short caudal peduncle, and a range of body coloration (Figure 3a, b, c)
We found no significant differences in countable traits among EG, NG, and RCC, the lateral line scale count in CC (36.0) was significantly different from that in the other three variants (EG 27.7, NG 28.9, RCC 28.2)

Summary

Introduction

Distant hybridization can generate transgressive hybrid phenotypes that lead to the formation of new populations or species with increased genetic variation. We produced an experimental hybrid goldfish (EG) by distant crossing of red crucian carp (Carassius auratus) × common carp (Cyprinus carpio) followed by gynogenesis. Fertilizing the diploid eggs produced by G1 with diploid sperm from male ATs yielded a new tetraploid hybrid (G1 × AT, 4n = 200). This new species has a number of advantages over AT individuals, including origin and diversification of goldfish, and the role of distant hybridization during transgression and speciation

Methods

Results

Discussion

Conclusion