Maternally induced sterility in animals
The present invention provides Maternal Sterility Constructs (MSC) and methods of producing sterile progeny lacking germ cells. Female fish carrying the MSC transgene will give rise to a sterile generation, as the MSC specifically eliminates Progenitor Germ Cells (PGCs) of her progeny. These females are called lineage ending females. Male fish carrying the MSC transgene, however, give rise to fertile progeny (assuming the male is not derived from an MSC-transgenic female). Thus, MSC transgenic males can be used to propagate the transgenic line. The invention can be advantageously applied to provide effective population control and improve culture performance of farmed species, such as fish.
1. A method of propagating a hemizygous Maternal Sterility Construct (MSC) transgenic male fish comprising:
(i) obtaining a MSC comprising: (a) a promoter that is specifically active in a developing oocyte during oogenesis; (b) a pro-apoptotic polynucleotide sequence that ablates primordial germ cells (PGCs) after fertilization of the oocyte; and (c) a germ-cell-specific 3′ untranslated region (UTR), wherein (a), (b), and (c) are operably linked;
(ii) introducing the MSC to a fish embryo to generate a male MSC-transgenic founder fish carrying the construct in its germ cell;
(iii) identifying and breeding the MSC-transgenic male founder fish from step (ii) to produce a hemizygous MSC-transgenic male fish carrying the construct in its germ cell; and
(iv) breeding the hemizygous MSC-transgenic male fish with a female fish of the same species lacking the MSC to produce a lineage ending female progeny that express MSC and is fertile; and a hemizygous MSC-transgenic male progeny that expresses the MSC;
wherein the method is carried out in a fish species with germ cells that are specified by maternally inherited determinants according to a pre-formation process.
2. The method of claim 1 , further comprising breeding the hemizygous MSC-transgenic male progeny from step (iv) with a female fish of the same species lacking the MSC to propagate a line of hemizygous MSC-transgenic male fish.
3. The method of claim 1 , further comprising breeding the lineage-ending female progeny with a male fish of the same species to generate a sterile progeny.