Overview

Genetics is the blueprint of life. It explores how information is stored in DNA, how it is translated into proteins, and how variations in this code lead to the diversity of life on Earth.

Core Idea

The Central Dogma of Molecular Biology describes the flow of genetic information: $$ \text{DNA} \rightarrow \text{RNA} \rightarrow \text{Protein} $$

Formal Definition (if applicable)

Gene: A distinct sequence of nucleotides forming part of a chromosome, the order of which determines the order of monomers in a polypeptide or nucleic acid molecule.

Intuition

If a cell is a factory, DNA is the master instruction manual kept in the office (nucleus). RNA is a photocopy of a specific page sent to the factory floor (ribosome) to build a specific machine (protein).

Examples

  • Mendel’s Peas: The discovery of dominant and recessive traits.
  • Human Genome Project: Mapping all the genes in human DNA.
  • CRISPR: A technology for editing genes.

Common Misconceptions

  • “One gene = one trait.” (Most traits, like height or intelligence, are polygenic—influenced by many genes.)
  • “Genes determine everything.” (Environment and epigenetics play a huge role in how genes are expressed.)
  • Allele: A variant form of a gene.
  • Genotype vs. Phenotype: The genetic makeup vs. the observable characteristics.
  • Mutation: A change in the DNA sequence.

Applications

  • Medicine: Diagnosing and treating genetic disorders (e.g., Cystic Fibrosis).
  • Agriculture: Genetically modifying crops for pest resistance.
  • Forensics: DNA profiling.

Criticism / Limitations

Genetic determinism (the idea that genes alone decide our fate) has been criticized for ignoring environmental factors and for its historical misuse in eugenics.

Further Reading

  • Watson & Crick, Molecular Structure of Nucleic Acids
  • Mendel, Experiments on Plant Hybridization
  • Dawkins, The Selfish Gene