Trait Inheritance
1. Intro: The Father of Genetics
- Gregor Mendel is often referred to as the “Father of Genetics”
2. The Father of Genetics: Mendel’s Experiments & Heredity
- Genetics: the study of heredity
- Model system: a system, with convenient characteristics used to study
a specific biological phenomenon to be applied to other systems
- The Blending Theory of Inheritance: results from the action of
many genes to determine a characteristic (i.e. human height)
● Offspring appear to be a “blend” of their parents’ traits
- Continuous variation: the original parental traits were lost/absorbed
by the blending in the offspring
- Discontinuous variation: traits that were inherited in distinct classes
(i.e. violets vs. white flowers)
● Showed that traits were not blended in the offspring, nor were
they absorbed
● Instead, they kept their distinctness and could be passed on
- Hybridizations: involve mating 2 true-breeding individuals that have
different traits (hybrid = mixture)
● Plants used in first-generation crosses were called Po, or
parental generation one, plants
● Offspring = F1, or first filial generation (filial = offspring,
daughter/son)
- Trait: a variation in the physical appearance of a heritable
characteristic
● Characteristics: plant height, seed texture, seed color, pea pod
size, pea pod color, and flower position
- Expressed & Latent traits = Dominant & Recessive traits
● Dominant traits: traits that are inherited unchanged in a
hybridization
● Recessive traits: traits that become LATENT, or disappear, in
the offspring of a hybridization
❖ The recessive trait does reappear in the progeny
(offspring) of the hybrid offspring
1. Intro: The Father of Genetics
- Gregor Mendel is often referred to as the “Father of Genetics”
2. The Father of Genetics: Mendel’s Experiments & Heredity
- Genetics: the study of heredity
- Model system: a system, with convenient characteristics used to study
a specific biological phenomenon to be applied to other systems
- The Blending Theory of Inheritance: results from the action of
many genes to determine a characteristic (i.e. human height)
● Offspring appear to be a “blend” of their parents’ traits
- Continuous variation: the original parental traits were lost/absorbed
by the blending in the offspring
- Discontinuous variation: traits that were inherited in distinct classes
(i.e. violets vs. white flowers)
● Showed that traits were not blended in the offspring, nor were
they absorbed
● Instead, they kept their distinctness and could be passed on
- Hybridizations: involve mating 2 true-breeding individuals that have
different traits (hybrid = mixture)
● Plants used in first-generation crosses were called Po, or
parental generation one, plants
● Offspring = F1, or first filial generation (filial = offspring,
daughter/son)
- Trait: a variation in the physical appearance of a heritable
characteristic
● Characteristics: plant height, seed texture, seed color, pea pod
size, pea pod color, and flower position
- Expressed & Latent traits = Dominant & Recessive traits
● Dominant traits: traits that are inherited unchanged in a
hybridization
● Recessive traits: traits that become LATENT, or disappear, in
the offspring of a hybridization
❖ The recessive trait does reappear in the progeny
(offspring) of the hybrid offspring
