Genetics and Selective Breeding

Genetics and DNA

• DNA is the genetic code for living organisms and is used to identify animals with high genetic merit.
• DNA structure is crucial for genetic improvement.

Genetic Improvement

• Physical traits are visible features of an animal, such as the Aberdeen Angus being naturally polled.
• The gene for the polled condition is dominant over the gene for the presence of horns.

Selective Breeding

• Line breeding is a technique used in selective breeding.
• Double muscling is an example of a physical trait, caused by a mutation in the myostatin gene that controls muscle growth.

Performance Testing and Progeny Testing

• Performance testing and progeny testing are used to establish the genetic potential of a bull.
• The results of progeny testing are used to develop a genetic profile for bulls.

Genotyping and Genomic Selection

• Genomics is the study of an animal's DNA.
• Genotyping is a technique used to identify differences in an animal's DNA.
• Scientists have identified positions on the DNA of cattle, known as SNPs, that are related to important traits such as carcass weight, fertility, and milk yield.
• Genotyping and genomic selection have several advantages, including:
  • Increased accuracy in selection
  • Increased speed in breeding programs
  • Improved disease resistance
  • Improved fertility
  • Improved milk production

Natural Selection

• Natural selection is the process by which populations of living organisms adapt and change.
• The inheritance of two copies of a lethal gene is an example of natural selection.

Agricultural Biotechnology

• Biotechnology has been used to develop solutions to various problems, including:
  • Crop damage from weeds, diseases, or insects
  • Improved productivity
  • Increased food safety
• Applications of biotechnology include:
  • Genetic engineering
  • Molecular markers
  • Molecular diagnostics
  • Tissue culture

Genetic Engineering

• Genetic engineering involves the transfer of DNA to improve crops, animals, or microorganisms.
• Transgenic species are any organism that has had part of the DNA of another species inserted into its own DNA.
• Cisgenic describes an organism that has been modified with a gene from an organism of the same or closely related species.

Benefits and Risks of Genetic Engineering

• Benefits of genetic engineering include:
  • Increased crop yields
  • Improved disease resistance
  • Increased food safety
• Risks of genetic engineering include:
  • Potential long-term impacts on the environment and human health
  • Unintended consequences of genetic modification

Genomic Editing

• Genomic editing is the use of any technology that allows a change to an organism's DNA.
• Genetic material can be added, removed, or altered at specific locations in the genome.
• Genomic editing can be used to create new varieties in crops that are difficult to breed.
• CRISPR/Cas9 is a genomic editing tool that allows for precise editing of DNA sequences.