Module 1

Cards (122)

  • Animal domestication
    The process of adapting wild plants or animals to live in association with humans
  • Production requirements for animal domestication
    • Feeding and proper nutrition
    • Animal health
    • Specific selection of stock
  • Domestication began
    10,00020,000 BCE
  • Selective breeding
    Specific for improving growth, performance or any trait that is selected to improve genetic value and choose those who have the desired phenotype
  • Preventative medicine

    Includes culling decisions and dealing with genetic diseases
  • Genetic diseases are usually untreatable, so it is usually best to cull the affected animal from breeding stock
  • Herd genetics
    Can be determined through a variety of mating systems and selection methods and techniques
  • Purebred breeders

    Most likely to seek genetic advice because their main products for sale are the genes
  • The majority of genetic progress is done by purebred breeders or seed stock suppliers
  • Genetic traits and diseases
    Could be acquired in the following ways: Congenital, Familial, Inherited
  • Patterns of inheritance
    • Single gene
    • Chromosomal
    • Multifactorial
  • Teratogens are environmental or outside factors that influence the growth or traits of an individual and has nothing to do with the actual genetics
  • Family history
    Very important when looking at genetics, including factors such as age of parents, number of offspring and their sex, miscarriages or stillbirths or their breed
  • Autosomal
    Trait is passed on a gene that is NOT a sex chromosome
  • Autosomal dominant generalizations
    • Most are non enzyme protein disorders
    • Could have variable expressivity
    • Could have reduced or incomplete penetrance
    • Many are the result of a new mutation
    • Homozygote recessive is often lethal
  • Variable expressivity
    The degree to which a phenotypic trait can be seen
  • Reduced penetrance

    Either the presence or absence of a trait, where not all individuals with the allele express the phenotype
  • Many autosomal dominant traits are the results of new mutations within a species
  • Homozygous individuals for autosomal dominant traits usually results in early death
  • Dominance hierarchy
    The ordered patterns of dominance
  • Melanocortin Receptor 1 gene (MC1R)

    The gene that influences pigmentation
  • Melanocyte components
    • Nucleus
    • Mitochondrion
    • Rough ER
    • Golgi apparatus
    • Melanosomes
  • Phaeomelanin
    Responsible for producing red, yellow and cream pigments
  • Eumelanin
    Responsible for producing black, brown and gray pigments
  • Autosomal dominant inheritance
    Could be by codominance or incomplete dominance, where heterozygotes have a different phenotype than either homozygote
  • Codominance
    • Merle colouring in Australian Shepherds
  • Incomplete dominance
    • Palomino colour in horses
  • Autosomal recessive generalizations
    • Most are enzyme deficiencies
    • Phenotypes are presented consistently
    • Symptoms are usually severe
    • Usually passed down through generations
  • Enzyme deficiencies
    Arise from the inborn consequences of metabolism failure, often due to the build up of proteins that the lysosomes are unable to break down
  • If the phenotype is expressed by autosomal recessive inheritance, then the trait is usually consistent within families
  • Autosomal recessive diseases are usually severe, present at birth, and lethal if left untreated
  • Consanguinity
    The state where traits are passed on and present throughout generations due to inbreeding
  • The implication of autosomal recessive inheritance is to cull the affected individuals, as both parents are 'obligate' carriers with a 0% chance of unaffected offspring
  • Carrier detection tests
    Typically performed on parents who are carriers to see what the chances of affected offspring are
  • Breeding tests
    Involve mating a sire to an affected or heterozygous dam to see if affected offspring are born, to determine if the sire is a carrier
  • Direct tests
    Could be biochemical (testing proteins and enzymes) or DNA (PCR tests looking for mutations)
  • Indirect tests
    DNA linkage tests used when the causative gene is not known, to find a marker linked to the suspected gene
  • Sex linked inheritance
    Occurs when the gene is on the sex chromosome, with fewer genes
  • X inactivation
    Occurs in female mammals, where one of the X chromosomes is inactivated
  • X linked diseases
    • Muscular dystrophy in dogs, hemophilia in horses and dogs