Mutation
- It is a sudden heritable change in DNA sequences resulting in changes in the genotype and the phenotype of an organism.
- Mutation is of 2 types:
- Point mutation: The mutation due to a change (substitution) in a single base pair of DNA. E.g., sickle cell anemia.
- Frame-shift mutation: It is the deletion or insertion of base pairs resulting in the shifting of DNA sequences.
- Loss (deletion) or gain (insertion/duplication) of a DNA segment causes chromosomal abnormalities (aberrations).
- Chromosomal aberrations are seen in cancer cells.
- The agents which induce mutation are called mutagens. They include:
- Physical mutagens: UV radiation, α, β, γ rays, X-rays, etc.
- Chemical mutagens: Mustard gas, phenol, formalin, etc.
Pedigree Analysis
- In humans, control crosses are not possible. So the study of family history about inheritance is used.
- Such an analysis of genetic traits in several generations of a family is called pedigree analysis.
- The representation or chart showing family history is called a family tree (pedigree).
- In human genetics, a pedigree study is utilized to trace the inheritance of a specific trait, abnormality, or disease.
Symbols Used in Pedigree Analysis
Select a Topic 👇
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Topic 1: Mendel's Experiments
Topic 2: Inheritance of One Gene
Topic 3: Inheritance of Two Genes
Topic 4: Other Patterns of Inheritance
Topic 5: Chromosomal Theory, Morgan's Experiment
Topic 6: Sex Determination
Topic 7: Mutation and Pedigree Analysis
Topic 8: Genetic Disorders (Mendelian and Chromosomal)