Review: Meiosis Sperm Father’s Characteristics Egg Mother’s Characteristics + Zygote Sexual Reproduction and Genetics Chapter 10

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 Mendelian Genetics Sexual Reproduction and Genetics Chapter 10

 The passing of traits to the next generation is called inheritance, or heredity Mendelian Genetics Sexual Reproduction and Genetics  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

 The parent generation is also known as the P generation. Sexual Reproduction and Genetics 10.2 Mendelian Genetics Chapter 10

Sexual Reproduction and Genetics  The second filial (F 2 ) generation is the offspring from the F 1 cross Mendelian Genetics Chapter 10  The offspring of this P cross are called the first filial (F 1 ) generation.

 Mendel studied seven different traits. Sexual Reproduction and Genetics  Seed or pea color – Yellow or Green  Flower color – Purple or White  Seed pod color – Yellow or Green 10.2 Mendelian Genetics Chapter 10

 Mendel studied seven different traits. Sexual Reproduction and Genetics  Seed shape or texture – Round or Wrinkled  Seed pod shape – Inflated or Constricted  Stem length – Tall or Dwarf  Flower position – Axial or Terminal 10.2 Mendelian Genetics Chapter 10

Genes in Pairs Sexual Reproduction and Genetics  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 Mendelian Genetics Chapter 10

Dominance Sexual Reproduction and Genetics  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 10.2 Mendelian Genetics Chapter 10

Dominance Sexual Reproduction and Genetics  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 Mendelian Genetics Chapter 10

Genotype and Phenotype Sexual Reproduction and Genetics  An organism’s allele pairs are called its genotype.  The observable characteristic or outward expression of an allele pair is called the phenotype Mendelian Genetics Chapter 10

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

Sexual Reproduction and Genetics 10.2 Mendelian Genetics Chapter 10  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.

Sexual Reproduction and Genetics 10.2 Mendelian Genetics Chapter 10 Genotype and Phenotype? Yellow is dominant to green.

Sexual Reproduction and Genetics 10.2 Mendelian Genetics Chapter 10 Genotype and Phenotype? Yellow is dominant to green.