Genetics

What you'll learn

• Describe the central questions of genetics and its history from blending inheritance and Mendel to the chromosome theory, the identification of DNA as the genetic material and modern genome editing, and explain the role of model organisms and the lessons of the eugenics movement.
• Explain Mendel’s laws of segregation and independent assortment, predict genotypic and phenotypic ratios for monohybrid, dihybrid and multi-gene crosses using Punnett squares and the product method, and use testcrosses to infer genotypes.
• Apply the product and sum rules, the binomial distribution and conditional probability to genetic problems, and test observed ratios against expected ratios with a chi-square goodness-of-fit test, interpreting degrees of freedom, P values and statistical power.
• Explain dominance in terms of protein function, and analyse incomplete dominance, codominance, multiple alleles including the ABO blood groups, lethal alleles, penetrance, expressivity, pleiotropy and genotype–environment interaction.
• Interpret modified dihybrid ratios such as 9 : 3 : 4, 9 : 7, 12 : 3 : 1 and 15 : 1 as forms of epistasis, relate them to biochemical pathways, and use complementation tests to assign mutations to genes.
• Describe chromosome structure and karyotype notation, explain how meiosis produces segregation, independent assortment and genetic variety, and interpret tetrad analysis in fungi.
• Compare sex-determination systems, explain X inactivation and dosage compensation, predict the inheritance of X-linked and Y-linked traits, and analyse pedigrees to identify modes of inheritance and calculate carrier risks with Bayesian methods.
• Calculate recombination frequencies from testcrosses, construct genetic maps from three-point crosses including gene order and interference, relate map distance to physical distance, and interpret LOD scores in human linkage studies.
• Explain how nondisjunction produces aneuploidy, describe common human aneuploidies and the effect of maternal age, analyse polyploidy and structural rearrangements including translocations and inversions, and discuss prenatal screening in its Canadian or American context.
• Classify gene mutations and their effects, explain spontaneous and induced mutation, interpret the fluctuation test and the Ames test, describe the major DNA repair pathways and their links to disease, and explain the nature and importance of transposable elements.
• Explain continuous variation with the polygenic model, define and estimate broad- and narrow-sense heritability, predict response to selection with the breeder’s equation, and calculate the effects of selection, mutation–selection balance and inbreeding on genotype frequencies.
• Explain mitochondrial inheritance, maternal effect, genomic imprinting and epigenetics, describe the types and ethics of genetic testing and counselling, compare Canada’s Genetic Non-Discrimination Act with the US GINA, explain the Canadian prohibition on heritable genome editing, and analyse a family case with combined risk calculations.