Mendelian Inheritance Principles

Mendelian Inheritance

Key Principles:

• The Law of Segregation: Each pair of alleles separates from each other during gamete formation, resulting in each gamete receiving only one allele.
• The Law of Independent Assortment: Alleles for different genes are sorted independently of each other during gamete formation, resulting in a random combination of alleles.
• The Law of Dominance: One allele can be dominant over another allele, resulting in the dominant allele being expressed in the phenotype.

Mendel's Experiments:

• Studied the inheritance of traits in pea plants (Pisum sativum)
• Cross-pollinated plants with different traits (e.g., tall vs. short, green vs. yellow)
• Analyzed the resulting F1 and F2 generations to understand the inheritance patterns

Mendelian Inheritance Patterns:

• Autosomal Dominant: One copy of the dominant allele is enough to express the trait (e.g., Huntington's disease)
• Autosomal Recessive: Two copies of the recessive allele are needed to express the trait (e.g., cystic fibrosis)
• X-Linked Dominant: One copy of the dominant allele on the X chromosome is enough to express the trait (e.g., Rett syndrome)
• X-Linked Recessive: Two copies of the recessive allele on the X chromosome are needed to express the trait (e.g., hemophilia)

Punnett Squares:

• A graphical representation of the possible genotypes and phenotypes of offspring from a cross between two parents
• Used to predict the probability of different genotypes and phenotypes in the offspring
• Helps to visualize and understand the inheritance patterns of traits

Genetic Terminology:

• Genotype: The genetic makeup of an individual (e.g., BB or Bb)
• Phenotype: The physical expression of the genotype (e.g., blue eyes or brown eyes)
• Homozygous: Having two copies of the same allele (e.g., BB or bb)
• Heterozygous: Having one copy of each of two different alleles (e.g., Bb)

Mendelian Inheritance

Key Principles

• The Law of Segregation: each pair of alleles separates during gamete formation, resulting in each gamete receiving only one allele.
• The Law of Independent Assortment: alleles for different genes are sorted independently during gamete formation, resulting in a random combination of alleles.
• The Law of Dominance: one allele can be dominant over another allele, resulting in the dominant allele being expressed in the phenotype.

Mendel's Experiments

• Studied inheritance of traits in pea plants (Pisum sativum) through cross-pollination of plants with different traits (e.g., tall vs. short, green vs. yellow).
• Analyzed F1 and F2 generations to understand inheritance patterns.

Mendelian Inheritance Patterns

• Autosomal Dominant: one copy of the dominant allele expresses the trait (e.g., Huntington's disease).
• Autosomal Recessive: two copies of the recessive allele express the trait (e.g., cystic fibrosis).
• X-Linked Dominant: one copy of the dominant allele on the X chromosome expresses the trait (e.g., Rett syndrome).
• X-Linked Recessive: two copies of the recessive allele on the X chromosome express the trait (e.g., hemophilia).

Punnett Squares

• A graphical representation of possible genotypes and phenotypes of offspring from a cross between two parents.
• Used to predict probability of different genotypes and phenotypes in offspring.
• Helps visualize and understand inheritance patterns of traits.

Genetic Terminology

• Genotype: genetic makeup of an individual (e.g., BB or Bb).
• Phenotype: physical expression of the genotype (e.g., blue eyes or brown eyes).
• Homozygous: having two copies of the same allele (e.g., BB or bb).
• Heterozygous: having one copy of each of two different alleles (e.g., Bb).