Production of androgenetic tiger barb, Puntius tetrazona

Abstract

The protocol for successful induction of androgenetic cloning of the tiger barb, Puntius tetrazona, with contrasting gray and blond strains is described. At the intensity of 4.2 W/m², the UV irradiation for 3.5 min totally inactivates the maternal genome in eggs of the gray barb. Following activation by the blond barb sperm, the 24-min-old eggs are shocked at 41°C for 2 min to restore diploidy. Maternal genomic inactivation is confirmed by (i) expression of green fluorescent protein (GFP) gene in 16-h-old haploid embryo; (ii) blond body colour in the diploid fry and adult; and (iii) progeny testing. Androgenetic males and females were reared to sexual maturity and their reproductive performance was evaluated. The performance of the supermales (YY) is superior to normal ones (XY), but that of androgenetic females (X²X²) is inferior to normal ones (X¹X²). Fifteen crosses involving five supermales and eight normal dams sire 97-100% male progenies, confirming the operation of XX♀:XY♂ sex determination system in the tiger barb. The unexpected occurrence of female progeny is a ubiquitous feature of supermales of at least half a dozen fish species.