Chapter 12 - Patterns of Inheritance Flashcards
What evidence contradicted the idea that traits are directly passed from parent to offspring?
Crossing hybrids led to some offspring resembling original strains rather than the hybrid strains.
Why did Gregor Mendel choose to study pea plants?
- pea hybrids could be produced
- many pea varieties available
- peas are small and easy to grow
- can self-fertilize or be cross-fertilized
What were the 7 characters Mendel studied in his experiments?
- purple vs white flowers
- yellow seeds vs green seeds
- round seeds vs wrinkled seeds
- green pods vs yellow pods
- inflated pods vs constricted pods
- axial flowers vs terminal flowers
- tall plants vs dwarf plants
Mendel’s experimental method:
- produce true-breeding strains for each trait he was studying
- cross-fertilize true-breeding strains having alternate forms of trait
- perform reciprocal crosses as well - allow hybrid offspring to self-fertilize and count # of offspring showing each form of the trait
Monohybrid cross:
a cross to study only 2 variations of a single trait
F1 generation (1st filial generation):
offspring produced by crossing 2 true-breeding strains
F2 generation:
offspring resulting from the self-fertilization of F1 plants
Dominant:
the form of each trait expressed in the F1 plants
Recessive:
the form of the trait not seen in the F1 plants
Dominant to Recessive ratio in F2 plants (phenotype):
3:1
Genotype ratio in F2 plants:
1 true-breeding dominant: 2 non-true-breeding dominant: 1 true-breeding recessive
Gene:
information for a trait passed from parent to offspring
Alleles:
alternate forms of a gene
homozygous
having 2 of the same allele
heterozygous
having 2 different alleles
