Lecture Notes on Genetics and Inheritance

Introduction to Genetics and Information Flow

• Information Flow in Biology
  • Previous focus: Information flow within a cell (DNA to proteins)
  • New focus: Information flow between cells and generations (Genetics)
• Definition of Genetics
  • Study of genes and their inheritance
  • Influence on phenotype: Observable traits influenced by genes

Basics of Genes and Central Dogma

• What is a Gene?
  • Molecular biology perspective: DNA segment encoding RNA and proteins
  • Historical perspective: Functional unit of heredity
• Central Dogma of Molecular Biology
  • DNA encodes RNA, which encodes proteins

Historical Context of Genetics

• Early Human Influence on Genetics
  • 10,000 years ago: Non-shattering wheat leading to agriculture
  • 4,000 years ago: Domestication of almonds (sweet almonds)
  • Influence on food (wheat, almonds) and clothing (cotton)

Modern Applications of Genetics

• DNA and Personal Genetics
  • Genetic testing services (23andMe, etc.)
  • Usefulness and privacy concerns
• Forensics and Genetics
  • Example: Golden State killer case solved with DNA
  • DNA genotyping in criminal investigations
  • Privacy issues related to genetic data

Fundamentals of Genetics

• Physical Model of Inheritance
  • Cell division as a mechanism for inheritance
  • Chromosome segregation
• Chromosome Structure
  • Chromosomes have centromeres and arms
  • Haploid vs. Diploid
    • Haploid (1 set, e.g., gametes: eggs and sperm)
    • Diploid (2 sets, most body cells)

Cell Division: Mitosis vs. Meiosis

• Mitosis
  • Cloning of a cell (2n to 2n)
  • Genetically identical cells produced
• Meiosis
  • Reduction division (2n to 1n)
  • Produces haploid gametes
  • Two stages: Meiosis I (reductional), Meiosis II (equational)

Demonstration of Chromosome Segregation

• Mitosis Demonstration
  • Alignment along the spindle, equal segregation
• Meiosis Demonstration
  • Homologous chromosomes pair and segregate
  • Importance of accurate segregation to prevent disorders (e.g., Down syndrome)

Implications and Future Lectures

• Potential Errors in Segregation
  • Non-disjunction leading to genetic disorders and cancer
• Preview of Upcoming Topics
  • Mendelian inheritance, fruit flies, genetic mapping
  • DNA sequencing and genome studies

Conclusion: Understanding genetics provides insight into biology, human history, and modern applications such as personalized medicine and forensic science.