→INTRO TO GENETICS
Gregor Mendel “Father of Genetics”
⭐︎Inheritance of Traits Laws
- Austrian monk
- Studied the inheritance of traits in pea plants
- Not recognized until the turn of the 20th century
- Found that the plants’ offspring retained traits of the parents.
- Stated that physical traits are inherited as “particles”
→ particles were actually chromies & DNA
● Why pea plants?
- Can be grown in a small area
- Many offspring
- Produce pure plants when allowed to self pollinate several generations.
- Can be artificially cross-pollinated.
- Pollen contains sperm (stamen)
- Ovary contains eggs (inside flower)
1. Pollen carries sperm to eggs for
fertilization
2. Self-fertilization can occur in the same
flower
3. Cross fertilization can occur between
flowers.
● Pea plants studied by Mendel
Character Studied Dominant (R) Recessive (r)
Seed shape smooth wrinkled
Seed color yellow green
Pod shape inflated wrinkled
Pod color green yellow
Flower color purple white
Flower position on stem on tip
Plant height tall dwarf
Seed coat colour gray white
, → GENETIC TERMINOLOGY
● Trait: any characteristic that can be passed from parent to
● Heredity: passing of traits from parent to offspring
● Genetics: study of heredity
Types of Genetic Crosses
● Monohybrid: cross involving a single trait
→ flower color
● Dihybrid: cross involving two traits
→ flower color & plant height
Designer “Genes”
● Alleles: two forms of a gene
→ Dominant: stronger of two genes expressed in hybrid.
represented by capital letter (R).
→ Recessive: gene that shows up less often in hybrid.
represented by lowercase letter (r).
● Genotypes: gene combo for a trait
→ RR, Rr, rr
● Phenotype: the physical feature resulting from a genotype
→ red, white
→ GENOTYPES
● Homozygous dominant: 2 dominant alleles (RR) ~ pure
● Homozygous recessive: 2 recessive alleles (rr) ~ pure
● Heterozygous genotype: 1 dom & 1 recessive allele (Rr) ~ hybrid
Gen “Gap”
● P1 (parental) gen: parental gen in breeding experiment.
● F1 gen: first gen offspring in breeding experiment.
→ from breeding individuals from the P1 gen
● F2 gen: second gen offspring in breeding experiment.
→ from breeding the F1 gen.
Gregor Mendel “Father of Genetics”
⭐︎Inheritance of Traits Laws
- Austrian monk
- Studied the inheritance of traits in pea plants
- Not recognized until the turn of the 20th century
- Found that the plants’ offspring retained traits of the parents.
- Stated that physical traits are inherited as “particles”
→ particles were actually chromies & DNA
● Why pea plants?
- Can be grown in a small area
- Many offspring
- Produce pure plants when allowed to self pollinate several generations.
- Can be artificially cross-pollinated.
- Pollen contains sperm (stamen)
- Ovary contains eggs (inside flower)
1. Pollen carries sperm to eggs for
fertilization
2. Self-fertilization can occur in the same
flower
3. Cross fertilization can occur between
flowers.
● Pea plants studied by Mendel
Character Studied Dominant (R) Recessive (r)
Seed shape smooth wrinkled
Seed color yellow green
Pod shape inflated wrinkled
Pod color green yellow
Flower color purple white
Flower position on stem on tip
Plant height tall dwarf
Seed coat colour gray white
, → GENETIC TERMINOLOGY
● Trait: any characteristic that can be passed from parent to
● Heredity: passing of traits from parent to offspring
● Genetics: study of heredity
Types of Genetic Crosses
● Monohybrid: cross involving a single trait
→ flower color
● Dihybrid: cross involving two traits
→ flower color & plant height
Designer “Genes”
● Alleles: two forms of a gene
→ Dominant: stronger of two genes expressed in hybrid.
represented by capital letter (R).
→ Recessive: gene that shows up less often in hybrid.
represented by lowercase letter (r).
● Genotypes: gene combo for a trait
→ RR, Rr, rr
● Phenotype: the physical feature resulting from a genotype
→ red, white
→ GENOTYPES
● Homozygous dominant: 2 dominant alleles (RR) ~ pure
● Homozygous recessive: 2 recessive alleles (rr) ~ pure
● Heterozygous genotype: 1 dom & 1 recessive allele (Rr) ~ hybrid
Gen “Gap”
● P1 (parental) gen: parental gen in breeding experiment.
● F1 gen: first gen offspring in breeding experiment.
→ from breeding individuals from the P1 gen
● F2 gen: second gen offspring in breeding experiment.
→ from breeding the F1 gen.
