mendel

• Gregor Mendel


  Father of Genetics
• Gregor Mendel


  • Biologist
  • Mathematician
  • Meteorologist
  • Born July 20, 1822
• History of Gregor Mendel

  1. Lived in a monastery in Austria in 1842

  2. Moved to the University of Vienna in 1851 where he studied science and mathematics

  3. Returned to monastery, taught, & kept a garden (most famous for studies on peas)
• Mendel's Pea Plant Experiment conducted between 1856 to 1863
• Characters of pea plants observed by Mendel


  • Height of plant's stem (tall or short)
  • Position of flower on stem (mid-stem or end of stem)
  • Pod Color (green or yellow)
  • Pod Appearance (smooth or bumpy)
  • Seed Texture (round or wrinkled)
  • Seed Color (green or yellow)
  • Flower Color (purple or white)
• Character


  Physical features that are inherited
• Trait


  One of several possible forms of a character
• Hybrid


  Offspring of a cross between parents with different traits
• Mendel's Initial Observation (Experiment)

  1. Crossed (mated) purple flowered peas plants with white flowered pea plants

  2. All the offspring had purple flowers

  3. Two of these first offspring were crossed, and some of their offspring had purple flowers, but a few had white flowers
• True-Breeding


  A plant that is pure for a trait; when self-pollinated, its offspring will always have that same trait
• P₁ generation


  The original parents
• Mendel's Experiment


  1. Used true-breeding plants

  2. Cross-pollinated two P₁ generation plants of contrasting traits, their offspring were labeled the F₁ generation

  3. An F₁ generation plant was allowed to self-pollinate, its offspring were labeled the F₂ generation
• Allele


  Alternate versions of a gene
• Homozygous genotype


  Two identical alleles
• Heterozygous genotype


  Two different alleles
• Genotype


  All the alleles/genes inherited; an individual's genetic information
• Phenotype


  The physical expression of one's genotype
• Dominant Allele


  The allele whose trait is always expressed
• Recessive Allele


  Not expressed when a dominant allele is present
• Multiple Alleles


  A trait has 3 or more possible alleles (an individual still has only 2 alleles for the trait)
• Codominance


  Both alleles for a trait are fully expressed
• Incomplete Dominance


  An allele does not completely dominate another; phenotype will be a blend
• Punnett Square


  Model/tool that predicts the outcomes of a genetic cross
• Monohybrid Cross


  Cross between individuals involving one trait
• Other term for f1 generation

  first filial generation
• Other term for f2 generation

  Second filial generation