Download HeredityGen

Chapter 8
Mendel & Heredity
Chapter Overview
•
•
•
•
8.1 Mendel’s Experiment
8.2 Theory and Law of Heredity
8.3 Punnett Squares
8.4 Complex Patterns of Heredity
Topic #1-8.1 Origin of Genetics
• 1800s before DNA
• Gregor Mendel
– Austrian monk intrigued with “heredity”
• Passing of traits from parents to offspring
– Designed an experiment to show how “genes”
were passed down
• Bred pea plants for color patterns 7 years
• Observed inheritance patterns
Topic #2- Mendel’s Experiment
• Monohybrid Cross
– 1 trait flower color
Based on this experiment
he came up with 4
hypotheses…
Mendel’s Hypotheses
• 1. Alternating forms of genes called alleles
Mendel’s Hypotheses
2. For each trait organism has 2 alleles
– Same 2 alleles = homozygous (AA, aa)
– Different alleles = heterozygous (Aa)
Mendel’s Hypotheses
3. When only 1 of the 2 traits in a
heterozygous organisms is visible the
allele is dominant (R) the non visible is
recessive (r)
Mendel’s Hypotheses
4. The 2 alleles for a character separate during meiosis
(gametes) Principle of segregation!!
Topic #3- What Mendel’s Experiment Show Us
Today
• Every organism has a genotype
– Genetic makeup (AA, Aa, aa)
• Every organism has a phenotype
– Observable (Purple, Purple, White)
REVIEW
What are the genotypes for
Homozygous dominant:
Heterozygous:
Aa
Homozygous recessive:
What is a Genotype?
What is a Phenotype?
What is an Allele?
AA
aa
Monohybrid Practice problems
•
•
•
•
Cross H. Dominant X Heterozygous
Cross H. Recessive X Heterozygous
Cross Heterozygous X Heterozygous
Cross H. Dominant X H. Recessive
Practice Worksheet