Genotype

Genotype refers to the genetic makeup of an organism, which is responsible for the specific traits and characteristics that an individual possesses. It is the complete set of genes contained within the DNA of an organism.

Key Concepts

• Genes: Genes are units of heredity that are passed down from parent to offspring. Each gene carries specific instructions for the production of a particular protein or characteristic.
• Alleles: Alleles are different forms of a gene that can occupy the same position (locus) on a chromosome. For example, the gene for eye color may have alleles for blue eyes, brown eyes, etc.
• Homozygous and Heterozygous: An organism is homozygous for a particular gene if it carries two identical alleles for that gene (e.g., BB or bb). Heterozygous organisms carry two different alleles for a particular gene (e.g., Bb).
• Phenotype: The observable traits and characteristics of an organism, which are determined by its genotype and environmental influences.

Mendelian Inheritance

The principles of genotype inheritance were first described by Gregor Mendel through his experiments with pea plants. Mendel's laws of inheritance, including the law of segregation and the law of independent assortment, provide the foundation for understanding how genotypes are passed from one generation to the next.

Genetic Disorders

Understanding genotypes is crucial in the study of genetic disorders. Some genetic disorders are caused by mutations in specific genes, leading to abnormal phenotypic traits. Examples include cystic fibrosis, sickle cell anemia, and Huntington's disease.

Study Tips

• Review the basics of DNA and genetic inheritance.
• Practice Punnett squares to understand how genotypes are inherited from parents.
• Explore examples of genetic disorders and their underlying genotypes.
• Discuss the impact of environmental factors on the expression of genotypes.