04 2025S 490 Genomes _ Genetics_1-62

Page 4: Outline of Viral Genomes

• Topics Covered:

  • Genome principles and the Baltimore system

  • Structure/complexity of viral genomes

  • Characteristics of viral sequences

  • Coding strategies in viruses

  • Implications of genome size

  • Origin and genetic analysis of viruses

Page 5: Viral Terminology

• Strands:

  • Positive (+) and negative (-) strands defined.

  • mRNA as the positive strand; complementary strand is negative (-).

  • Ambisense RNA contains both (+) and (-) sequences.

Page 6: Viral Genome Complexity

• Types of Viral Genomes:

  • DNA or RNA, circular, linear, segmented, gapped, etc.

Page 7: Encoded Information in Viral Genomes

• Gene products:

  • Required for genome replication, expression, assembly, host defense modulation, and spread.

Page 8: Non-Encoded Information

• Missing Gene Information:

  • Complete protein synthesis machinery, membrane biosynthesis proteins, telomeres, and centromeres generally absent.

Page 9: Ribosomal Protein Genes in Viruses

• Eukaryotic virus example:

  • Some eukaryotic viruses encode ribosomal proteins, while many viral genomes lack coding for complete synthesis machinery.

Page 10: Viral Genome Principles

• Main Principles:

  • Viral genome as a repository for replication and transmission information.

  • All must produce mRNAs for host ribosome use.

  • Seven major types of viral genomes show evolutionary unity in genetic diversity.

Page 11-12: The Baltimore System

• Integration of Principles:

  • Deduce mRNA production steps based on genome nature.

  • Universal function: serves as a template for progeny genome synthesis excluded.

Page 13: DNA vs. RNA Viruses

• Challenges:

  • DNA viruses use existing cellular mechanisms; RNA viruses require their replication mechanisms encoded in their RNA.

Page 14-15: Structure of DNA Genomes

• General Characteristics:

  • Diverse structures (linear, circular, etc.) dictate different replication mechanisms.

Page 16: Course Continuation

• Date: 02/27/2025

Page 17-19: Viruses in the News

• Measles:

  • High pre-vaccination death rates, vaccination statistics needed to prevent outbreaks.

• Public Concerns:

  • Controversy around misinformation, vaccination advocacy.

Page 20-24: Structure of DNA Genomes (Continued)

• Gapped and ssDNA:

  • Importance of completing gapped DNA before mRNA synthesis.

  • ssDNA genome replication and mRNA production mechanisms covered.

Page 25-27: RNA Genome Structures

• RNA Virus Enzymes:

  • Encode necessary RNA-dependent RNA polymerases.

Page 28: Seminar Information

• Upcoming Talk:

  • "Zoonotic Disease in Hawaiʻi and the Pacific" by Dr. Michael Norris.

Page 29-30: Pandemic Research Concerns

• Safety Protocols:

  • High safety standards for research on potentially dangerous viruses necessary.

Page 31-34: ss(-) RNA Genomes

• Translation Challenges:

  • Require viral RdRP to produce (+) strand mRNA for translation.

Page 35-36: Viral Genome Structures

• Viral Assembly:

  • Naked or encapsidated structures, engaging in complex folded shapes.

Page 37-39: Coding Strategies

• Complex Tactics:

  • Utilize multiple strategies to maximize protein production from genomes.

Page 40-62: Current Events and Gene Analysis

• Measles Outbreaks:

  • Responses observed include medical advice against misinformation.

• Genetic Analysis Methodologies:

  • Evolutionary insights gained from analyzing viral genetic diversity.