Introduction to Genetics

Genetics, the study of inheritance, is a fundamental property of all living things and has combined with natural selection to produce the diversity and complexity of life on this planet.

Intoduction to Genetics

  • Three fundamental questions
    1. How are traits (phenotypes) passed from one generation to another (inherited)?
    2. How does the genotype determine the phenotype?
    3. How do populations evolve?
  • Two main approaches have been used to answer these questions
    1. the study of the pattern of inheritance of traits in the progeny of specific matings (transmission genetics)
    2. the study of the pieces (molecular genetics)
  • Modern transgenic studies combine the two approaches

A Brief History of Biology

  • like begets like
    • epigenesis - structures arise de novo (Aristotle, Harvey)
    • preformationism - homunculus grows into adult
  • Cells (Schleiden and Schwann, 1830)
    • organisms are composed of cells that are composed of atoms
  • the species type - fixed and unchanging species
    • requires special creation (Linnaeus)
  • inheritance of acquired characteristics (Lamarck, early 1800's)
  • Evolution by natural selection (Darwin, 1859)
  • Germplasm (Weisman, 1863)
  • Particulate inheritance (Mendel, 1866)
    • no blending
    • genotype determines phenotype
  • Mendel's principals were rediscovered in 1900
  • Chromosomal theory of inheritance (early 1900's)
  • Population genetics (Fisher and Haldane, 1930's)
    • evolution is caused by changes in allele frequencies in populations
  • one gene one polypeptide (Beadle & Tatum, 1940's)
  • DNA is the genetic material (Avery, 1944)
  • the Double Helix (Watson and Crick, 1953)
    • showed how information could be passed from generation to generation
  • mRNA (Jacob, Brenner, and Meselson, 1961)
    • transcription of DNA into RNA
  • colinearity of gene and protein (Yanofsky, 1964)
  • the genetic code (1960's)
    • translation of RNA into protein
  • the Central Dogma of Molecular Biology (1960's)
    • DNA to RNA to protein to phenotype
  • Recombinant DNA (Cohen and Boyer, 1973)
    • cloning and biotechnology
  • Genomics (1990's)
    • sequencing of entire genomes

Bell CSU Chico Library
This document is copyright of Jeff Bell
Last Update: Wednesday, August 12, 1998