Patterns of Inheritance
Chapter 9: Patterns of Inheritance
What pattern will inheritance follow?
Why is it important?
Always follow patterns?
Rule of Probability
In tossing a coin the odds of either a head or tail is always 50%.
The outcome is unaffected by the previous attempt.
If 2 coins are tossed, each will be dependent of the other
HH, HT, TH, TT (Probability is 25% or ¼)
The rules also hold true for genetics due to the law of independent assortment.
Each alternative type of outcome in a gene acts independently of the other possible outcomes.
Alleles:
Each of the possible forms a gene is called an allele.
Most genes will have 2 alleles.
Dominant – The allele that appears most frequently.
Recessive – The allele that appears least frequently.
Dominant v. Recessive:
Dominant – Freckles, Widows Peak, Free Earlobe
Recessive – No Freckles, Straight Hair Line, Attached Earlobe.
Mendel’s Peas:
Gregor Mendel was the father of modern genetics.
Used common garden peas to study traits.
Easy to use due to short life span, self pollination and readily distinguishable traits.
Was a follow up on Darwin’s work.
7 – Different pea traits.
Flower Color
Pod Shape
Flower Position
Stem Length
Pod Color
Seed Shape
Seed Color
Pollination:
Self pollination – Pollen grains land on carpals (pistil) of the same flower.
Cross Pollination – Pollen crosses to another flower.
Generations of Mendel’s Plants:
P Generation – Parent
F1 – First offspring
F2 – Second offspring of F, xF, Cross.
Mendel used true breeding plants so he would be sure he crossed only the traits he wanted.
Monohybrid vs. Dihylorid:
Mono – Only concerned with one trait at a time (Eg. Flower color, Seed Color, or Seed Shape).
Di – Two traits at a time (Eg. Flower Color and Seed Color).
How do we use the traits?
The Dominant traits are given a capital letter to stand for that trait (Eg. R for round, Y for yellow).
The Recessive trait is given a lower case letter (Eg. r for wrinkled, y for green).
What pattern will inheritance follow?
Why is it important?
Always follow patterns?
Rule of Probability
In tossing a coin the odds of either a head or tail is always 50%.
The outcome is unaffected by the previous attempt.
If 2 coins are tossed, each will be dependent of the other
HH, HT, TH, TT (Probability is 25% or ¼)
The rules also hold true for genetics due to the law of independent assortment.
Each alternative type of outcome in a gene acts independently of the other possible outcomes.
Alleles:
Each of the possible forms a gene is called an allele.
Most genes will have 2 alleles.
Dominant – The allele that appears most frequently.
Recessive – The allele that appears least frequently.
Dominant v. Recessive:
Dominant – Freckles, Widows Peak, Free Earlobe
Recessive – No Freckles, Straight Hair Line, Attached Earlobe.
Mendel’s Peas:
Gregor Mendel was the father of modern genetics.
Used common garden peas to study traits.
Easy to use due to short life span, self pollination and readily distinguishable traits.
Was a follow up on Darwin’s work.
7 – Different pea traits.
Flower Color
Pod Shape
Flower Position
Stem Length
Pod Color
Seed Shape
Seed Color
Pollination:
Self pollination – Pollen grains land on carpals (pistil) of the same flower.
Cross Pollination – Pollen crosses to another flower.
Generations of Mendel’s Plants:
P Generation – Parent
F1 – First offspring
F2 – Second offspring of F, xF, Cross.
Mendel used true breeding plants so he would be sure he crossed only the traits he wanted.
Monohybrid vs. Dihylorid:
Mono – Only concerned with one trait at a time (Eg. Flower color, Seed Color, or Seed Shape).
Di – Two traits at a time (Eg. Flower Color and Seed Color).
How do we use the traits?
The Dominant traits are given a capital letter to stand for that trait (Eg. R for round, Y for yellow).
The Recessive trait is given a lower case letter (Eg. r for wrinkled, y for green).