Transcript Sexual Reproduction and Genetics

Chapter 10
Sexual Reproduction and Genetics
Review: Meiosis
Sperm
Father’s
Characteristics
+
Egg
Mother’s
Characteristics
Zygote
Chapter 10
Sexual Reproduction and Genetics
10.2 Mendelian Genetics
Gregor Mendel’s 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.
Chapter 10
Sexual Reproduction and Genetics
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.
Chapter 10
Sexual Reproduction and Genetics
10.2 Mendelian Genetics
 The parent generation is also known as the
P generation.
Chapter 10
Sexual Reproduction and Genetics
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.
Chapter 10
Sexual Reproduction and Genetics
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
Chapter 10
Sexual Reproduction and Genetics
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
Chapter 10
Sexual Reproduction and Genetics
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.
Chapter 10
Sexual Reproduction and Genetics
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
Chapter 10
Sexual Reproduction and Genetics
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.
Chapter 10
Sexual Reproduction and Genetics
10.2 Mendelian Genetics
Genotype and Phenotype
 An organism’s allele pairs are called its
genotype.
 The observable characteristic or outward
expression of an allele pair is called the
phenotype.
Chapter 10
Sexual Reproduction and Genetics
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)
Chapter 10
Sexual Reproduction and Genetics
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.
Chapter 10
Sexual Reproduction and Genetics
10.2 Mendelian Genetics
Genotype and Phenotype?
Yellow is dominant to green.
Chapter 10
Sexual Reproduction and Genetics
10.2 Mendelian Genetics
Genotype and Phenotype?
Yellow is dominant to green.