A transgenic non-human animal model is disclosed. The system comprises an inducible transgene allowing the expression of a mutant POLG1 polypeptide that results in modulation of mitochondrial DNA copy number and/or concentration in the whole transgenic non-human animal or selected cells or tissues of the transgenic non-human animal. Methods of producing and using the model system are also provided.

Described herein are methods and compositions for autocatalytic genome editing and neutralizing autocatalytic genome editing. The autocatalytic genome editing may be based on genomic integration of a construct containing multiple elements or on a trans-complementation approach, in which genetic elements can be propagated separately. The disclosure provides a method for autocatalytic genome editing based on the CRISPR/CAS9 system, and methods of use thereof, in animals, humans, and plants for eliminating pathogens, targeting suppression of crop pests, strategies to combat virus (e.g., HIV) and other diseases (e.g., cancer) caused by retrovirus, as well as to generate homozygous mutations that are transmitted to nearly all offspring.

Systems and methods relate to transgenic organisms and their use as biosensors are described. In some embodiments, the systems and methods include a first population of transgenic organisms that includes a first constitutively expressed reporter gene, and a first transgene that includes a first inducible promoter from a response pathway gene, wherein the first inducible promoter is coupled to a first reporter gene. Other embodiments are described.

A genetically modified mouse is provided that comprises a conditional Acvr1 allele that comprises a mutated exon that, upon induction, converts to a mutant exon phenotype, wherein the mutant exon phenotype includes ectopic bone formation. Mice comprising a mutant Acvr1 exon 5 in antisense orientation, flanked by site-specific recombinase recognition sites, are provided, wherein the mice further comprise a site-specific recombinase that recognizes the site-specific recombinase recognitions sites, wherein the recombinase is induced upon exposure of the mouse to tamoxifen. Upon exposure to tamoxifen, the recombinase is expressed and acts on the RRS-flanked mutant exon 5 and places the mutant exon 5 in sense orientation and deletes the wild-type exon.

A genetically modified rodent is provided that comprises a modified Acvr1 gene that comprises a conditional altered exon 7 encoding R258G in anti sense orientation, flanked by site-specific recombinase recognition sites, wherein the altered exon is inverted to sense orientation upon action of a recombinase, resulting in ectopic bone formation.

Livestock animals and progeny thereof comprising at least one edited chromosomal sequence that alters expression or activity of a somatostatin receptor (SSTR) protein are provided. Livestock animal cells that contain such edited chromosomal sequences are also provided. The livestock animals have improved growth performance and weight gain. Methods for producing livestock animals with increased growth performance are also provided.

Provided are a three-dimensional pancreatic organoid derived from the pancreas of a genetically modified mouse, a method for fabricating the three-dimensional pancreatic organoid, and use of the three-dimensional pancreatic organoid for drug effect verification and/or drug screening.

A genetically modified mouse is provided that comprises a conditional Acvr1 allele that comprises a mutated exon that, upon induction, converts to a mutant exon phenotype, wherein the mutant exon phenotype includes ectopic bone formation. Mice comprising a mutant Acvr1 exon 5 in antisense orientation, flanked by site-specific recombinase recognition sites, are provided, wherein the mice further comprise a site-specific recombinase that recognizes the site-specific recombinase recognitions sites, wherein the recombinase is induced upon exposure of the mouse to tamoxifen. Upon exposure to tamoxifen, the recombinase is expressed and acts on the RRS-flanked mutant exon 5 and places the mutant exon 5 in sense orientation and deletes the wild-type exon.

A genetically modified mouse is provided that comprises a conditional Acvr1 allele that comprises a mutated exon that, upon induction, converts to a mutant exon phenotype, wherein the mutant exon phenotype includes ectopic bone formation. Mice comprising a mutant Acvr1 exon 5 in antisense orientation, flanked by site-specific recombinase recognition sites, are provided, wherein the mice further comprise a site-specific recombinase that recognizes the site-specific recombinase recognitions sites, wherein the recombinase is induced upon exposure of the mouse to tamoxifen. Upon exposure to tamoxifen, the recombinase is expressed and acts on the RRS-flanked mutant exon 5 and places the mutant exon 5 in sense orientation and deletes the wild-type exon.

A knock-in non-human mammal comprising a recombinant androgen receptor (AR) cassette containing an exogenous human polyglutamine (polyQ) tract encoding sequence in exon 1, wherein the human polyQ tract encoding sequence is stably integrated into the genome of the animal. Also provided are recombinant cells, fertilized eggs and tissues. The resulting animal displays a wide range of phenotypes, best characterized as Metabolic Syndrome and can be used in screening and other assays.