MODULE 1 – INTRODUCTION TO GENETICS & CYTOGENETICS

Page 1: Introduction

  • Genetics for Dentistry

  • Title: "Genetics: An Introduction: History, Cytogenetics, and State of Science in the Field"

  • Instructor: Clint Daryll Suarez

Page 2: Topics to Be Discussed

  • Key Terms

  • History of Genetics

  • History of Cytogenetics

  • Genetics and Cytogenetics

  • Development

Page 3: Key Terms (Hartl, 2020)

  • Genetics: Study of biologically inherited traits, influenced by the environment.

  • Genomics: Study of all genes in an organism to understand their organization, function, interaction, and evolutionary history.

Page 4: Key Terms (Kannan & Zilfalil, 2009)

  • Cytogenetics: Study of the structure and properties of chromosomes, behavior during somatic cell division (mitosis) and germ cell division (meiosis), and influence on phenotype.

Page 5: Chromatin Structure

  • Nucleosomes: Basic units of DNA packaging.

  • Chromosomes are formed by super-coiling DNA and histones.

  • Deoxyribonucleic acid (DNA): The genetic material of living organisms.

Page 6: History of Genetics

  • Overview of the development of genetic science.

Page 7: The Term "Gene"

  • Origin from Darwin (1868, 1871) and Hugo de Vries (1889): Concept of "pangenesis" — heritable information from gemmules aggregated in gonads contributing to offspring.

  • Greek origins: "Pan" (all, whole) and "genesis" (birth).

Page 8: The Term "Gene" (continued)

  • Wilhelm Johannsen introduced the term "gene" as the functional unit of heredity, derived from Greek origins meaning offspring and procreation.

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Page 10: Gregor Mendel (1856)

  • Recognized as the father of modern genetics.

  • Conducted experiments with garden peas and published findings on heritable elements in 1866, known as Mendelian genetics.

Page 11: Mendelian Genetics

  • Mendel's Laws of Inheritance:

    • Law of Dominance: Only dominant traits are expressed in the phenotype.

    • Law of Segregation: Two gene copies segregate to offspring - one inherited from each parent.

    • Law of Independent Assortment: Alleles segregate independently.

Page 12: Friedrich Miescher (1869)

  • Discovered nuclein (later identified as DNA) in the nuclei of salmon sperm and white blood cells.

Page 13: The DNA as the Molecule of Heredity

  • Structure: DNA is a double helix, right-handed, with antiparallel chains.

  • Polarity: 5' end (trunk) and 3' end (tail).

Page 14: Base Pairing in DNA

  • Adenine (A) pairs with Thymine (T) and Cytosine (C) pairs with Guanine (G).

Page 15: The DNA as the Molecule of Heredity (continued)

  • Martha Chase and Alfred Hershey's experiment (1952): Confirmed DNA as the genetic material.

    • Experiment 1 used radiolabeled proteins; no radioactivity entered cells.

    • Experiment 2 used radiolabeled DNA; radioactivity observed in cells, concluding DNA is the key genetic material.

Page 16: History of Cytogenetics

  • Summary of significant findings in cytogenetics over time.

Page 17: Carl Wilhelm von Nägeli (1842)

  • Described thread-like structures in plant cell nuclei; identified as chromosomes later.

  • Walther Flemming (1870): Observed chromosomal behavior during cell division.

Page 18: Walter Sutton and Theodor Boveri (1904)

  • Proposed the chromosome theory of heredity: Chromosomes occur in matched pairs, one from each parent.

Page 19: Joe Hin Tjio and Albert Levan (1956)

  • Confirmed humans possess 23 pairs (46 total) chromosomes, correcting previous estimates.

Page 20: Chromosome Per Species

  • Chromosome counts vary among species:

    • Amoeba: 12

    • Mosquito: 6

    • Drosophila: 8

    • Corn: 20

    • Dog: 78

    • Chimps: 48

    • Cat: 38

    • Horse: 64

    • Elephant: 56

Page 21: The Term "Genome"

  • Hans Winkler (1920) coined "genome" uniting the concepts of gene and chromosome - meaning "I become, I am born" in Greek.

Page 22: DNA and Genome

  • Genome: Complete set of DNA in an organism, made up of chromosomes and genes.

Page 23: The Human Genome Project (2003)

  • Completed in 2003, mapping 3.2 billion base pairs and 50,000-150,000 genes over 13 years.

Page 24: Genetics and Cytogenetics Developments

  • Current state of genetic science focusing on technological advancements and applications.

Page 25: Key Branches of Genetics

  • Areas of genetic study include:

    • Cytogenetics

    • Mendelian Genetics

    • Molecular Genetics

    • Plant & Animal Genetics

    • Microbial Genetics

    • Population Genetics

Page 26: Molecular Genetics

  • Covers DNA sequencing, assembly, gene annotations, and function.

Page 27: Molecular Genetics: DNA Extraction

  • Workflow for DNA sequencing outlined, including PCR and gel electrophoresis.

Page 28: Karyotyping

  • Karyotyping is the process of pairing and ordering chromosomes, including fluorescence in situ hybridization (FISH) to detect mutations.

Page 29: Questions?

Page 30: Conclusion

  • Recap of the content covered in the introduction to genetics.