Breeding Lesson 1

Lesson 1.1

(Overview of Animal Breeding and Genetics: Origins and Roles)

  1. What is Animal Breeding?

  • application of principles of animal genetics

  • goal is to improve genetics of animals in terms of quantity, and production.

  1. Five important aspects of Animal Breeding

  • trait is heritable.

  • animals have different genetic backgrounds.

  • direction of selection is defined by humans.

  • animal breeding works at population level (breeding can be judged by looking at a shift in population average phenotype)

  • Success is a result of multiple generations of selection. Breeding decisions are made with the future in mind.

  1. Natural Selection and Evolution

  • Charles Darwin - it is not us but the environment that determines survival and reproductive success of animals.

  1. Domestication process

  • Behavioral traits (able to herded)

  • Reproductive traits (breed in captivity)

  • Physiological traits (adapt to husbandry)

  1. Three Pathways of Animal Domestication

  • Commensal pathway - animals attracted to human settlement, then captive as source of food

  • Prey pathway - capture of artiodactyl as supply of meat

  • Directed pathway - riding or draught animals

  1. Pre-requisites for Domestication

  • Animals should adopt to the type of feed they are offered by humans

  • Must survive and reproduce in closed quarters

  • Should be naturally calm

  • Willing to recognize humans as superior

  1. Origin of Animal Breeding: History of Science

  • Robert Bakewell

    - introduced keeping accurate records, and progeny testing

    - used inbreeding to fix characteristics

    - his farm is model of scientific management

    - “breed the best to best”

    - founder of Classical Animal Breeding

  • Jay Laurence Lush

    -father of Modern Scientific Animal Breeding

    -advocated that instead of subjective appearance, animal breeding should be based on combination of quantitative statistics and genetic information

    - authored “Animal Breeding Plans”

    - “Breed the best to best and hope for the best”

  • Lanoy Nelson Hazel

    -developed selection index theory (used to determine what weights should be put on the different traits under selection)

  • Charles Roy Henderson

    -developed the estimated breeding value (EBV)

  • he then improved the accuracy of the estimated breeding value by deriving the best linear unbiased prediction (BLUP) of the EBV in 195, but the term is used in 1960

  • Charles Darwin

    - “we cannot produce as perfect and as useful breeds; the key is man’s power of accumulative selection.”

  • Ronald Aylmer Fisher, Sewall Wright, J.B.S. Haldane

    -founders of Theological population genetics and quantitative genetics.

    -diversity of traits could depend on the involvement of Mendelian factors (genes)

  • Theo Meuwissen and Mike Goddard

    -developed large scale DNA information to estimate genomic breeding value

Lesson 2.2

(Disciplines and Foci of Animal Genetics)

  1. What is animal genetics?

  • study of the principles of inheritance in animals

  • William Bateson, “science dealing with heredity and variation seeking to discover laws governing similarities and differences in individuals related by descent.

  1. Three Main Areas in Animal Genetics

  • Mendelian genetics

  • Population genetics

  • Quantitative or Biometrical genetics

  • Molecular Development Genetics

  • Allied Fields

I. Mendelian or Classical Genetics

  • early studies on the behavior and mode of transmission of the units (genes) of heredity

  • Gregor Johann Mendel - published the Laws of Particulate Inheritance

  • William Bateson - deals with heredity and variation (animals), coined “homozygote”, “heterozygote”, and “allelomorph”

  • Wilhelm Ludvig Johannsen - introduced “genotype and phenotype”

II. Population Genetics

  • genetics composition of the population

  • goal: increase frequency of desirable genes and eliminate deleterious genes

III. Quantitative Genetics

  • inheritance of quantitative characters

  • many genes contribute to the expression of traits (milk yield, growth rate, litter size)

  • most difficult but the most important of the three areas

  • Ronald Aylmer Fischer and Sewall Green Wright - demonstrated that Mendelian frequences were the bases of biometrical correlations

IV. Molecular Genetics

  • structure and function of genes at molecular level

  • identification of: causal mutations to genetic conditions, gene variants underlying phenotype variation

  1. Animal Breeding in the Philippines

  • Bienvenido Maria Sioco Gonzales - developed Philamin cattle, Berkjala pigs, and Los Banos Cantonese chickens