Transgenic Disruption of Aromatase Using the Daughterless Construct to Alter Sex Ratio in Common Carp, Cyprinus Carpio

Abstract

The common carp (Cyprinus Carpio) is considered as invasive alien species (IAS) in North America and is particularly ecologically damaging in Australia. Traditional methods, biological means, harvesting and chemicals, used to control these aggressive invasive species do not adequately reduce population numbers. A Daughterless construct, which uses a shRNAi approach to silence aromatase, and then subsequently a reduction in estrogen, has been successfully tested in medaka (Oryzias latipes) and zebrafish (Danio ratio). The P1 transgenic common were produced by electroporation of a Daughterless Carp construct, pDC1, containing a shRNAi sequence targeting common carp aromatase and driven by the common carp aromatase promoter into sperm and eggs. Exposure to this construct either from the plasmid containing this sex reversal gene, integration of the transgene or both, resulted in a skewness towards maleness in the P1 as expected. P1 transgenic common carp males were mated with non-transgenic females to produce 42 F1 transgenic families. Paradoxically, the sex ratio for the F1 transgenic common carp progeny was biased towards femaleness, 3.0♀:1.0, compared to that of the non-transgenic F1 transgenic common carp progeny, 1.3♀: 1.0♂. Genetic, environmental or epigenetic effects resulted in a population that was gravitating towards sonless. Theoretically, this approach or result might be used for long-term population control.