Related Experiment Video

Updated: Aug 15, 2026

Bacterial Artificial Chromosomes: A Functional Genomics Tool for the Study of Positive-strand RNA Viruses
12:20

Bacterial Artificial Chromosomes: A Functional Genomics Tool for the Study of Positive-strand RNA Viruses

Published on: December 29, 2015

The advantage of sex in the RNA virus phi6

L Chao1, T T Tran, T T Tran

  • 1Department of Zoology, University of Maryland, College Park 20742, USA.

Genetics
|February 7, 1998
PubMed

Insights

Experiments with RNA bacteriophage phi6 show that while genetic drift reduces fitness, sex provides a significant advantage. This finding supports Muller's ratchet theory for the evolution of sex in viruses.

Area of Science:

  • Evolutionary Biology
  • Virology
  • Genetics

Background:

  • Laboratory populations of RNA bacteriophage phi6 exhibit decreased fitness under intensified genetic drift.
  • Deleterious mutations suggest Muller's ratchet may operate in these viruses, but this alone doesn't guarantee a sex advantage.

Purpose of the Study:

  • To investigate the role of population size in the observed lack of significant sex advantage in phi6.
  • To determine if sex confers a significant fitness advantage to phi6 populations.

Main Methods:

  • Subjecting phi6 populations to bottlenecks and subsequent crosses.
  • Repeating experiments with larger population sizes to assess the impact of sample size.
  • Quantifying fitness recovery through mutations and hybrid vigor.

Main Results:

  • Bottlenecked phi6 populations recovered fitness via mutations.
  • Hybrids showed additional fitness recovery beyond mutation effects, indicating a significant advantage of sex.
  • The advantage of sex was statistically significant and greater than zero.

Conclusions:

  • The results provide indirect support for Muller's ratchet as a mechanism driving the evolution of sex in phi6.
  • An alternative model to Muller's ratchet for the evolution of sex is proposed based on the experimental design and findings.

More Related Videos

An Assay for Quantifying Protein-RNA Binding in Bacteria07:02

An Assay for Quantifying Protein-RNA Binding in Bacteria

Published on: June 12, 2019

Evaluating the Effect of Coated Filters and Pre-Filters on the Infectivity and Concentration of Aerosolized Phi6 Virus09:32

Evaluating the Effect of Coated Filters and Pre-Filters on the Infectivity and Concentration of Aerosolized Phi6 Virus

Published on: May 29, 2026

Related Concept Videos

Lytic Cycle of Bacteriophages01:30

Lytic Cycle of Bacteriophages

Bacteriophages, also known as phages, are specialized viruses that infect bacteria. A key characteristic of phages is their distinctive “head-tail” morphology. A phage begins the infection process (i.e., lytic cycle) by attaching to the outside of a bacterial cell. Attachment is accomplished via proteins in the phage tail that bind to specific receptor proteins on the outer surface of the bacterium. The tail injects the phage’s DNA genome into the bacterial cytoplasm. In the lytic replication...
Retrovirus Life Cycles01:10

Retrovirus Life Cycles

Retroviruses have a single-stranded RNA genome that undergoes a special form of replication. Once the retrovirus has entered the host cell, an enzyme called reverse transcriptase synthesizes double-stranded DNA from the retroviral RNA genome. This DNA copy of the genome is then integrated into the host’s genome inside the nucleus via an enzyme called integrase. Consequently, the retroviral genome is transcribed into RNA whenever the host’s genome is transcribed, allowing the retrovirus to...
Viral Mutations00:36

Viral Mutations

A mutation is a change in the sequence of bases of DNA or RNA in a genome. Some mutations occur during replication of the genome due to errors made by the polymerase enzymes that replicate DNA or RNA. Unlike DNA polymerase, RNA polymerase is prone to errors because it is not capable of “proofreading” its work. Viruses with RNA-based genomes, like HIV, therefore accrue mutations faster than viruses with DNA-based genomes. Because mutation and recombination provide the raw material for adaptive...
Size and Structure of Viral Genomes01:26

Size and Structure of Viral Genomes

Viral genomes exhibit remarkable diversity in size, structure, and composition, influencing their replication strategies and interactions with host cells. These genomes consist of either DNA or RNA and may be linear or circular. Additionally, they can be single-stranded or double-stranded, with each configuration affecting how the virus propagates within a host. RNA viruses, for instance, generally have smaller genomes than DNA viruses, a factor that contributes to their high mutation rates and...
DNA Bacteriophages01:26

DNA Bacteriophages

Bacteriophages, or phages, are viruses that specifically infect bacteria, utilizing their genetic material to hijack host cellular machinery for replication. DNA bacteriophages employ single-stranded DNA (ssDNA) or double-stranded DNA (dsDNA) genomes. These phages exhibit diverse replication strategies and host interactions, influencing their ecological roles and applications in biotechnology and medicine.ssDNA BacteriophagesssDNA phages, with their small genomes, utilize unique strategies to...
Viruses with RNA Genomes01:29

Viruses with RNA Genomes

RNA viruses are categorized into positive-strand, negative-strand, or double-stranded groups based on their genomic structure and replication mechanisms. This classification dictates how they exploit host cellular machinery for protein synthesis and replication. Some RNA viruses also utilize reverse transcription as part of their life cycle, further diversifying their replication strategies.Positive-Strand RNA VirusesPositive-strand RNA viruses have genomes that function directly as messenger...