AP Biology Genetics
Gregor Mendel and His Research on Inheritance
1. Who is Gregor Mendel?
- Description: Mendel was an Austrian monk known for his pioneering quantitative studies of
inheritance by using garden peas.
2. Why Did Mendel Choose Garden Peas?
- Reasons:
- They exhibit alternate traits.
- They are true-breeding.
- They are small and easy to cultivate.
- Their fertilization can be easily controlled.
3. Mendel's Experimental Methodology:
- Steps:
1. Allowed plants to self-fertilize over many generations to produce true-breeding lines.
2. Crossed true-breeding plants.
3. Allowed the F1 generation to self-fertilize.
4. Counted and analyzed the offspring.
4. Mendel's Conclusions from His Experiments:
- Key Points:
- Traits are determined by "factors" (now known as genes).
- Each organism possesses two factors for each trait.
- These factors are inherited from both parents.
- Gametes carry only a single factor from each parent.
- Any gamete has an equal chance of carrying either factor.
, ### Key Genetic Terms and Concepts
5. Allele
- Definition: An alternative form of a gene.
- Example: For the gene determining flower color, possible alleles include purple or white.
6. Character
- Definition: A heritable feature that varies among individuals.
7. Trait
- Definition: A specific variant of a character.
8. Locus
- Definition: The specific location of a gene on a chromosome.
9. Dominant Allele
- Definition: An allele that expresses its trait if present in the genotype.
- Examples: Genotypes like RR, Rr, or rR include a dominant allele.
10. Recessive Allele
- Definition: An allele that is overshadowed by a dominant allele and can only manifest if the
dominant allele is absent.
- Example: rr is a homozygous recessive genotype.
11. Genotype
- Definition: The genetic constitution of an organism regarding a specific trait.
- Examples: Possible genotypes include RR, Rr, rR, and rr.
Gregor Mendel and His Research on Inheritance
1. Who is Gregor Mendel?
- Description: Mendel was an Austrian monk known for his pioneering quantitative studies of
inheritance by using garden peas.
2. Why Did Mendel Choose Garden Peas?
- Reasons:
- They exhibit alternate traits.
- They are true-breeding.
- They are small and easy to cultivate.
- Their fertilization can be easily controlled.
3. Mendel's Experimental Methodology:
- Steps:
1. Allowed plants to self-fertilize over many generations to produce true-breeding lines.
2. Crossed true-breeding plants.
3. Allowed the F1 generation to self-fertilize.
4. Counted and analyzed the offspring.
4. Mendel's Conclusions from His Experiments:
- Key Points:
- Traits are determined by "factors" (now known as genes).
- Each organism possesses two factors for each trait.
- These factors are inherited from both parents.
- Gametes carry only a single factor from each parent.
- Any gamete has an equal chance of carrying either factor.
, ### Key Genetic Terms and Concepts
5. Allele
- Definition: An alternative form of a gene.
- Example: For the gene determining flower color, possible alleles include purple or white.
6. Character
- Definition: A heritable feature that varies among individuals.
7. Trait
- Definition: A specific variant of a character.
8. Locus
- Definition: The specific location of a gene on a chromosome.
9. Dominant Allele
- Definition: An allele that expresses its trait if present in the genotype.
- Examples: Genotypes like RR, Rr, or rR include a dominant allele.
10. Recessive Allele
- Definition: An allele that is overshadowed by a dominant allele and can only manifest if the
dominant allele is absent.
- Example: rr is a homozygous recessive genotype.
11. Genotype
- Definition: The genetic constitution of an organism regarding a specific trait.
- Examples: Possible genotypes include RR, Rr, rR, and rr.
