Chapter 8 Outline: Mendel and Heredity
The Origins of Genetics
Mendel’s Studies of Characters
Heredity
Mendel’s Breeding Experiments
Genetics
Useful Features in Peas
1
2
3
Traits Expressed as Simple Ratios
Hybrid Cross
Step 1
True-breeding
P generation
Step 2
F1 generation
Step 3
F2 generation
Mendel’s Results
Mendel’s Theory
A Theory of Heredity
Mendel’s Hypotheses
1.
2.
alleles
3.
dominant
recessive
4.
Mendel’s Findings in Modern Terms
Homozygous
Heterozygous
Genotype
Phenotype
The Laws of Heredity
The Law of Segregation
The Law of Independent Assortment
Studying Heredity
Punnett Squares
One Pair of Contrasting Traits
Monohybrid Cross
Dihybrid Cross
Determining Unknown Genotypes
Test cross
Outcomes of Crosses
Probability
Probability of a Specific Allele in a Gamete
Probability of the Outcome of a Cross
Inheritance of Traits
Pedigree
Autosomal or Sex-linked?
Sex-linked genes
Dominant of Recessive?
Heterozygous or Homozygous?
Complex Patterns of Heredity
Complex Control of Characters
Characters Influenced by Several Genes
Polygenic inheritance
Intermediate Characters
Incomplete dominance
Characters Controlled by Genes With Three or More Alleles
Multiple Alleles
Characters with Two Forms Displayed at the Same Time
Codominance
Characters Influenced by the Environment
Genetic Disorders
Sickle Cell Anemia
Cystic Fibrosis (CF)
Hemophilia
Huntington’s Disease (HD)
Treating Genetic Disorders
Gene Therapy