Two or more conditional, dominant, lethal gene expression systems provide high levels of penetrance in insects. Lethality is induced at an earlier stage of development and the risk of biochemical resistance is reduced, as compared to a single insect conditional, dominant, lethal gene expression system. The invention is useful for the control of insect populations.

The present invention generally relates to genetically modified swine wherein at least one allele of a SIGLEC1 gene has been inactivated and/or at least one allele of a CD163 gene has been inactivated. Genetically modified swine having both alleles of the SIGLEC1 gene and/or both alleles CD163 gene inactivated are resistant to porcine reproductive and respiratory syndrome virus (PRRSV). Methods for producing such transgenic swine are also provided.

Non-human animals, methods and compositions for making and using the same, are provided, wherein said non-human animals comprise a humanization of a Cluster of Differentiation 274 (CD274) gene. Such non-human animals may be described, in some embodiments, as having a genetic modification to an endogenous CD274 gene so that said non-human animals express a Programmed cell death ligand 1 (PD-L) polypeptide that includes a human portion and an endogenous portion (e.g., a non-human portion).

Non-human animals and offspring thereof comprising at least one modified chromosomal sequence in a gene encoding a CD163 protein are provided. Animal cells that contain such modified chromosomal sequences are also provided. The animals and cells have increased resistance to pathogens, including porcine reproductive and respiratory syndrome virus (PRRSV). The animals and offspring have chromosomal modifications of a CD163 gene. The invention further relates to methods of breeding to create pathogen-resistant animals and populations of animals made using such methods.

Methods and compositions are provided for generating F0 fertile XY female animals. The methods and compositions involve making XY pluripotent or totipotent animal cells, in vitro cell cultures, or embryos that are capable of producing a fertile female XY animal in an F0 generation. Such cells, embryos, and animals can be made by silencing a region of the Y chromosome. Optionally, the cells can also be cultured in feminizing medium such as a low-osmolality medium and/or can be modified to decrease the level and/or activity of an Sry protein. Methods and compositions are also provided for silencing a region of the Y chromosome in an XY pluripotent or totipotent animal cell, or in vitro cell cultures, embryos, or animals derived therefrom, by maintaining an XY pluripotent or totipotent animal cell in a feminizing medium. Methods and compositions are also provided for maintaining a population of XY pluripotent or totipotent animal cells in a feminizing medium and selecting cells or clones having increased capabilities for producing a fertile female XY animal in an F0 generation. Methods and compositions are also provided for screening for compounds with feminizing activity or for optimizing concentrations of components in feminizing media.

Transient MLLT3 overexpression in culture may be used to expand human HSCs in vitro, and thereby improve the efficiency and safety of HSC transplantation.

Embodiments provided herein relate to systems for synthetically-engineered reciprocal chromosomal translocation for gene insertion into a population of organisms such as insects.

The invention relates to gene drives, and in particular to genetic sequences and constructs for use in a gene drive. The invention is especially concerned with ultra-conserved and ultra-constrained sequences for use as a gene drive target with the aim of overcoming the development of resistance to the drive. The invention is also concerned with methods of suppressing wild type arthropod populations by use of the gene drive construct described herein.

The disclosure relates to Bovine germplasm of Bos taurus variety JE840003146074527. Included in the present disclosure are cells comprising the Bovine variety JE840003146074527. Also provided by the present disclosure are tissue cultures of cells, animals obtained from said cells, and parts thereof, including F1 spermatozoa. The disclosure further provides for methods of breeding, selecting, and using the germplasm to improve existing commercial cattle herds generated from in vitro fertilization methods and progeny cattle obtained from in vitro fertilization and implantation and artificial insemination methods.

The present invention provides tissues derived from animals, which lack any expression of functional alpha 1,3 galactosyltransferase (alpha-1,3-GT). Such tissues can be used in the field of xenotransplantation, such as orthopedic reconstruction and repair, skin repair and internal tissue repair or as medical devices.