Mendelian and Population Genetics in Animal Breeding Flashcards
Define the following terms:
Gene, Haplotype, Allele, Genotype, Phenotype
Gene – a piece of DNA that codes for a protein
Haplotype – set of DNA variations or polymorphisms that tend to be inherited together
Allele – one of two or more versions of a gene
Genotype – individuals collection of genes
Phenotype – biochemical or visual characteristics
Why is there a need for genetic improvement?
Low cost, high quality food, profit, competition, consumer demands, companion animals and wildlife
What are the sources of genetic variation?
Mutations – changes in the DNA, can be beneficial, neutral or harmful
Gene flow – movement of genes from one population to another
Sex – can introduce new gene combinations into a population, independent assortment and crossing over
What is the difference between qualitative and quantitative traits?
Qualitative traits are characterised by segregation in classical Mendelian ratios
Quantitative traits, also referred to as continuous traits, can be given a numerical value on a scale
What does a mutation in the Myostatin Gene cause?
Increases muscle mass and enhances racing performance in heterozygote whippets
How can gene frequency in an offspring be calculated?
Depends solely on gene frequencies in parents, if the gene frequency of two alleles in parents are p and q, then the genotype frequency in the progeny is p2, 2pq & q2
What three factors mean genotype and gene frequencies are relatively constant from one generation to the next?
Large populations, random mating & no selection, mutation or migration
Define the following terms: Phenotype, Genotype, environmental
Phenotype – an observed category or measurable level of performance for a trait in an individual
Genotype – the genetic make-up of an individual
Environmental – the effect that external, non-genetic factors have on animal performance
What are epigenetics?
Heritable changes in gene expressions that are not caused by changes in DNA sequence
