Mendelian Inheritance Quiz

Mendelian Inheritance

Key Concepts

• Mendel's Laws: Gregor Mendel's discoveries about the inheritance of traits in pea plants, which form the basis of modern genetics.
• Hereditary Units: Genetic factors that are passed from parents to offspring, influencing the development of traits.

The Laws of Mendelian Inheritance

1. The Law of Segregation: Each pair of alleles (different forms of a gene) separates during gamete formation, resulting in each offspring inheriting one allele.
   • Example: A flower with alleles R (red) and r (white) will produce gametes with either R or r.
2. The Law of Independent Assortment: Alleles for different genes are sorted independently during gamete formation.
   • Example: The allele for flower color (R/r) is sorted independently of the allele for seed shape (S/s).
3. The Law of Dominance: One allele can be dominant over another allele, resulting in the dominant trait being expressed.
   • Example: The R allele is dominant over the r allele, so a plant with the genotype Rr will have red flowers.

Mendelian Inheritance Patterns

• Autosomal Dominant: A dominant allele will always be expressed if an individual has one copy of the allele.
  • Example: Huntington's disease is an autosomal dominant disorder.
• Autosomal Recessive: A recessive allele will only be expressed if an individual has two copies of the allele.
  • Example: Cystic fibrosis is an autosomal recessive disorder.
• X-Linked: Traits linked to the X chromosome, which can result in different inheritance patterns in males and females.
  • Example: Hemophilia is an X-linked recessive disorder.

Punnett Squares

• A graphical tool used to predict the probability of offspring genotypes and phenotypes based on parental genotypes.
• Helps to visualize the possible combinations of alleles and determine the probability of each outcome.

Genotype and Phenotype

• Genotype: The genetic makeup of an individual, including the specific alleles they possess.
• Phenotype: The physical and behavioral characteristics of an individual, resulting from the interaction of their genotype and the environment.