Genetics and Selective Breeding in Animals

DNA Structure and Function

• DNA is the genetic code in living organisms, serving as a blueprint for growth and development.

Genetic Improvement

• Genetic improvement is achieved through selective breeding and performance testing to identify animals with high genetic merit.
• The goal of genetic improvement is to produce animals with desirable traits, such as increased productivity or improved disease resistance.

Physical Traits

• Physical traits, like the polled condition in Aberdeen Angus, are determined by dominant genes.
• The polled condition is a visible feature characterized by the absence of horns.

Selective Breeding

• Line breeding is used to select for specific traits, such as muscling or growth rate.
• The myostatin gene mutation is an example of a genetic variation that can result in double muscling.

Performance Testing

• Performance testing is used to evaluate individual animal performance, including traits like growth rate, milk production, or fertility.
• The results of performance testing are used to identify animals with desirable traits for breeding purposes.

Progeny Testing

• Progeny testing involves using offspring to assess the genetic potential of an animal.
• The results of progeny testing are used to develop genetic profiles, such as Estimated Breeding Values (EBVs).

Genotyping and Genomic Selection

• Genomics is the study of animal DNA, focusing on the structure, function, and evolution of genomes.
• Genotyping identifies genetic variations, such as Single Nucleotide Polymorphisms (SNPs), linked to specific traits.

Natural Selection

• Natural selection is the process by which organisms adapt and change based on their genetic fitness.
• It eliminates lethal genes that affect survival and reproduction, leading to the evolution of fitter populations.

Agricultural Biotechnology

• Agricultural biotechnology involves the application of genetic engineering, molecular markers, and molecular diagnostics to improve agricultural productivity.
• Examples of biotechnological applications include genetic engineering of crops, genetic testing of animals, and diagnostics for disease detection.

Principles of Genetic Engineering

• Genetic engineering involves the transfer of genes between organisms to introduce new traits or characteristics.
• Transgenic and cisgenic methods are used for genetic modification, with the goal of improving productivity, disease resistance, or nutritional content.

Genomic Editing

• Genomic editing involves the alteration of an organism's DNA at specific locations, allowing for precise genetic modifications.
• Technologies like CRISPR/Cas9 enable precise editing of genes, offering potential applications in agriculture and biotechnology.

Benefits and Risks

• The benefits of genetic engineering and editing include improved productivity, increased disease resistance, and enhanced nutritional content.
• The risks involve potential long-term impacts on the environment, human health, and animal welfare, as well as ethical considerations related to the use of genetic technologies.