Mendelian Inheritance Principles

Study Notes

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).

Description

Understand the fundamental principles of Mendelian inheritance, including the Law of Segregation, Law of Independent Assortment, and Law of Dominance. Learn how these laws govern the transmission of traits from one generation to the next.