MEMORIAL UNIVERSITY OF NEWFOUNDLAND
                                              DEPARTMENT OF BIOLOGY

   BIOLOGY 2250                            Principles of Genetics                                 Fall 2002


Schedule for Biology 2250, Part 1  -  Principles of (Mendelian) Genetics
Detailed topics

1. Mendelian Analysis (Chapter 2)
    - The Principle of Segregation: Monohybrid cross (3:1, 1:2:1, 1:1 ratios), test cross (Aa x aa), Genetic terminology
    - The Principle of Independent Assortment: Dihybrid cross (9:3:3:1), test cross (1:1:1:1), 4 phenotypes, 9 genotypes, 16 gamete combinations, human genetics (pedigrees: dominant vs recessive)
    -  Inheritance and Probability
    -  Sex Chromosomes and sex linkage: sex linked inheritance ( reciprocal cross), sex determination (XY: humans, drosophila; ZW birds and moths), pedigrees (sex-linked dominant, recessive)

2. Chromosome Theory of Inheritance (Chapter 3)
    - Mitosis and meiosis (prophase, metaphase, anaphase, telophase), contrast and compare mitosis and meiosis. Chromosomes and mendelian inheritance: correlation between the behaviour of genes and the behaviour of chromosomes. Homologous chromososmes.

3. Gene Linkage and chromosome mapping (Chapter 5)
    - Recombination: complete linkage (no recombination) vs recommbination. Dihyrid cross (parental and recombinant gametes). Trans vs. cis. Crossing over between non-sister chromatids. recombination fraction (RF), map distance.

4.  Extensions to Mendelian analysis (Chapter 4)
    - Dominance and multiple alleles: complete dominance, no dominance, incomplete dominance, co-dominance, > 2 alleles
    - Pleiotropy (one gene affects > 1 trait) recessive lethal , epistasis (gene interaction: > 1 gene affects a character) modified 9:3:3:1 ratio
    - Penetrance and expressivity: phenotype affected by varing degrees by variation in genetic background and the environement.
    - Polygenes and heritability (Chapter 25) Phenotype = Genotype + Environement. Many genes and the environement can result in continuously distributed phenotypes (weight, height etc.). Additive alleles: the more gene pairs the greater the number of phenotypic classes. Heritability H2 = (genetic variation)/ (genetic variation + environmental variation)

5. Linkage and gene mapping(Chapter 5)
    - 3 point test cross (trihybrid = 8 gamete types): interference, crossing over, mapping functions. Undetected multiple crossing over results in an underestimate of map distances
    - Tetrad analysis (Chapter 6): ordered tetrads, first and second division segregation (gene to centromere distance), ordered tetrads (gene mapping) PD, T, NPD

6.  Gene and Chromosome Mutations
        Chapter 15:
            - Somatic vs. germinal mutation: Mutant phenotypes
            - detecting mutations
        Chapter 17, 18:
           - changes in chromosome structure: Karyotype, deletion (deletion mapping), duplication, inversion (para- pericentric) inversion loop, reciprocal translocation (reduced recombination)
           - changes in chromosome number: euploidy, polyploidy (autoployploidy, allopolyploidy, triploid, tetraploid), aneuploidy (nondisjunction, monosomics, trisomics) human chromosome mutations