Review: Meiosis

1
Review Meiosis
Sexual Reproduction and Genetics
Chapter 10
Sperm Fathers Characteristics
Egg Mothers Characteristics

Zygote
2
Sexual Reproduction and Genetics
Chapter 10

• Gregor Mendels Peas
• Genetics the scientific study of heredity
• Gregor Mendel a monk from Austria, and is known
  as the father of genetics
• He did his most notable work with pea plants in
  his garden.

10.2 Mendelian Genetics
3
Sexual Reproduction and Genetics
Chapter 10
10.2 Mendelian Genetics

• The passing of traits to the next generation is
  called inheritance, or heredity.

• Mendel performed cross-pollination in pea plants.

• Mendel followed various traits in
  the pea plants he bred.
• A trait is a characteristic such as
  hair or eye color, and height.

4
Sexual Reproduction and Genetics
Chapter 10
10.2 Mendelian Genetics

• The parent generation is also known as the P
  generation.

5
Sexual Reproduction and Genetics
Chapter 10
10.2 Mendelian Genetics

• The offspring of this P cross are called the
  first filial (F1) generation.

• The second filial (F2) generation is the
  offspring from the F1 cross.

6
Sexual Reproduction and Genetics
Chapter 10
10.2 Mendelian Genetics

• Mendel studied seven different traits.

• Seed or pea color Yellow or Green

• Flower color Purple or White

• Seed pod color Yellow or Green

7
Sexual Reproduction and Genetics
Chapter 10
10.2 Mendelian Genetics

• Mendel studied seven different traits.

• Seed shape or texture Round or Wrinkled

• Seed pod shape Inflated or Constricted

• Stem length Tall or Dwarf

• Flower position Axial or Terminal

8
Sexual Reproduction and Genetics
Chapter 10
10.2 Mendelian Genetics
Genes in Pairs

• Allele

• An alternative form of a single gene passed from
  generation to generation
• Expressed as a letter
• (A or a, B or b, etc.)
• Found on the same location of homologous
  chromosomes.

9
Sexual Reproduction and Genetics
Chapter 10
10.2 Mendelian Genetics
Dominance

• An organism with two of the same alleles for a
  particular trait is homozygous.
• Example AA or aa

• An organism with two different alleles for a
  particular trait is heterozygous.
• Example Aa

10
Sexual Reproduction and Genetics
Chapter 10
10.2 Mendelian Genetics
Dominance

• A dominant trait needs only one copy of an allele
  to express its phenotype.

• A recessive trait requires two copies of an
  allele to express its phenotype.

11
Sexual Reproduction and Genetics
Chapter 10
10.2 Mendelian Genetics
Genotype and Phenotype

• An organisms allele pairs are called its
  genotype.

• The observable characteristic or outward
  expression of an allele pair is called the
  phenotype.

12
Sexual Reproduction and Genetics
Chapter 10
10.2 Mendelian Genetics

• Seed or pea color Yellow or Green

Seed color Phenotype Yellow or Green
Seed color Genotype Yellow (YY or Yy) Green (yy)
13
Sexual Reproduction and Genetics
Chapter 10
10.2 Mendelian Genetics

• Seed or pea color Yellow or Green

Yellow is dominant to green!! A dominant allele
will mask the expression of a recessive
allele. You only need one dominant allele to
represent yellow. Genotype Yellow (YY or
Yy) Green (yy)
YY or Yy
Must have two yy.
14
Genotype and Phenotype?
Sexual Reproduction and Genetics
Chapter 10
10.2 Mendelian Genetics
Yellow is dominant to green.
15
Genotype and Phenotype?
Sexual Reproduction and Genetics
Chapter 10
10.2 Mendelian Genetics
Yellow is dominant to green.