Genetics week 5

Study Notes

Somatic vs. Germline Mutations

Somatic mutations occur in non-reproductive body cells and are not heritable.
Germline mutations arise in reproductive cells and can be passed to future generations.
Germline mutations impact the entire organism while somatic mutations typically affect only the individual.
Examples of somatic mutations include those leading to lung or skin cancer, whereas germline mutations can cause conditions like sickle cell disease or cystic fibrosis.

Spontaneous vs. Induced Mutations

Spontaneous mutations happen naturally without external factors and contribute to genetic diversity.
Induced mutations result from exposure to mutagens, such as chemicals or radiation, influencing environmental factors.
Induced mutations are important for research in genetics and molecular biology.
Both spontaneous and induced mutations play roles in evolution, genetics, and medical advancements.

Back Mutations vs. Suppressor Mutations

Back mutations restore the original DNA sequence, reverting phenotype to its initial state.
Suppressor mutations do not change the original sequence but compensate for the effects of the original mutation.
Back mutations occur at the same location as the original mutation, whereas suppressor mutations can occur at different sites, within the same gene or another gene.
Understanding these types of mutations aids in genetic analysis and treatment of genetic disorders.

Phenylketonuria (PKU) and Albinism

PKU results from mutations affecting the metabolic pathway of phenylalanine, leading to its accumulation and brain damage if untreated.
Albinism is caused by mutations in the tyrosinase gene, resulting in the absence of melanin production.
A lack of tyrosinase affects the conversion of phenylalanine to tyrosine, impacting pigmentation in individuals with albinism.

Sickle Cell Anemia

Sickle cell anemia is caused by a point mutation in the HBB gene on chromosome 11, responsible for the beta-globin subunit of hemoglobin.
A single nucleotide alteration changes adenine to thymine, resulting in a codon shift from GAG to GTG.
This mutation replaces glutamic acid with valine at the sixth position of the beta-globin chain.
The abnormal hemoglobin causes red blood cells to become sickle-shaped under low oxygen conditions, leading to reduced flexibility and impaired blood flow.
Symptoms of sickle cell anemia include pain crises, organ damage, and increased infection risk due to altered hemoglobin structure and function.

Description

Explore the differences between somatic and germline mutations in this quiz. Understand their heritability, occurrence, and impact on organisms. Test your knowledge on how these mutations affect individuals and future generations.