Mendelian Basis of Mendelian Basis of InheritanceInheritance

Gregor Mendel- Father of GeneticsGregor Mendel- Father of Genetics

Studies of Gregor MendelStudies of Gregor Mendel

Mendel’s 4 PostulatesMendel’s 4 Postulates

Unit factors in pairsUnit factors in pairs Dominance /RecessivenessDominance /Recessiveness SegregationSegregation Independent AssortmentIndependent Assortment

Monohybrid CrossMonohybrid Cross

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Monohybrid CrossMonohybrid Cross

Genotype-genetic Genotype-genetic makeup of an makeup of an individualindividual

Phenotype-physical Phenotype-physical traits of an individual traits of an individual as expressed from as expressed from the genotypethe genotype

TestcrossTestcross

Problem SolvingProblem Solving:: 1. In a cross between a black and a white guinea pig, 1. In a cross between a black and a white guinea pig,

all members of the F1 generation are black. The F2 all members of the F1 generation are black. The F2 generation is made up of ¾ black and ¼ white guinea generation is made up of ¾ black and ¼ white guinea pigs. Diagram this cross, showing the genotypes and pigs. Diagram this cross, showing the genotypes and phenotypes.phenotypes.

2. Albinism in humans is inherited as a simple 2. Albinism in humans is inherited as a simple recessive trait. For the ff families, determine the recessive trait. For the ff families, determine the genotypes of parents and offspring. When two genotypes of parents and offspring. When two alternative genotypes are possible, list both. A. Two alternative genotypes are possible, list both. A. Two normal parents have five children, four normal and normal parents have five children, four normal and one albino. B. A normal male and an albino female one albino. B. A normal male and an albino female have six children, all normal. C. Which of the Mendel’s have six children, all normal. C. Which of the Mendel’s postulates are illustrated?postulates are illustrated?

Dihybrid CrossDihybrid Cross

Problem Solving:Problem Solving:

Mendel crossed peas having round seeds and yellow Mendel crossed peas having round seeds and yellow cotyledons with peas having wrinkled seeds and green cotyledons with peas having wrinkled seeds and green cotyledons. All the F1 plants had round seeds with cotyledons. All the F1 plants had round seeds with yellow cotyledons. Diagram this cross through the F2 yellow cotyledons. Diagram this cross through the F2 generation using both the Punnett square or branch generation using both the Punnett square or branch method.method.

With regard to the ABO blood types in humans, With regard to the ABO blood types in humans, determine the genotypes of the male parent and female determine the genotypes of the male parent and female parent: parent: Male ParentMale Parent: Blood type B whose mother was : Blood type B whose mother was type O type O Female Parent: Female Parent: Blood type ABlood type A whose father was whose father was type B. Predict the blood types of the offspring that this type B. Predict the blood types of the offspring that this couple may have and the expected proportion of each.couple may have and the expected proportion of each.

Principle of SegregationPrinciple of Segregation

Incomplete DominanceIncomplete Dominance

Multiple AllelismMultiple Allelism

Dominance/RecessivenessDominance/Recessiveness CodominanceCodominance

EpistasisEpistasis

Trihybrid CrossTrihybrid Cross

Human InheritanceHuman Inheritance