Genes and inheritance

Genes and inheritance

1. Ancient genetics

   • Pagenesis
     • Pangenes
   • Blending
     • intermediate trait

2. Mendel

   • Advantages of using pea plants (typically self-fertilize)
     • Controlled mating
     • easy self-fertilization / cross-fertilization
     • observable characteristics with 2 distinct forms
     • True-breeding strains
       • repeated self-fertilization
   • Characteristics
     • Flower colour
     • Flower position
     • Seed colour
     • Seed shape
     • Pod colour
     • Pod shape
     • Stem length
   • Law of segregation
     • Monohybrid cross
       • one trait disappear in F1
       • reappear in 1/4 of F2
       • a cross to track inheritance of one character
     • Four hypothesis
       • 1. Genes are found in diff versions as alleles
       • 2. Inheriting 2 alleles for each feature
       • 3. dominant v.s. recessive
       • 4. law of segregation
   • Law of independent assortment
     • Dihybird cross
       • non-parental combination appears
   • Test cross
     • determine unknown phenotype
     • mate with homozygous recessive
   • Probability
     • Rule of multiplication
     • Rule of addition

3. Non-Medelian

   • Incomplete dominance (four o-clock)
   • Multiple alleles - ABO
   • Codominance
     • ABO: alleles determine presence of oligosaccharide
   • Epistasis
   • Polygenic inheritance
   • Linked gene
   • Sex linked gene