Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Evolution of New Traits in Microbes01:24

Evolution of New Traits in Microbes

Microorganisms evolve rapidly due to their large population sizes and short generation times, often exhibiting measurable changes within days under laboratory conditions. Natural selection acts on standing genetic variation, enabling the retention and amplification of beneficial traits that confer fitness advantages in changing environments.Adaptive Pigment Regulation in RhodobacterIn Rhodobacter, a genus of purple non-sulfur bacteria, light-harvesting pigments such as bacteriochlorophyll and...
Antibiotic Selection00:57

Antibiotic Selection

Overview
Bioreactor Controls-III01:22

Bioreactor Controls-III

Strain improvement is a foundational strategy in industrial microbiology aimed at maximizing microbial productivity, particularly because natural isolates typically yield commercially valuable products in very low concentrations. Although optimizing the culture medium and environmental conditions can improve yields, these adjustments are inherently limited by the organism’s genetic potential. As a result, the focus shifts toward genetic modifications to enhance biosynthetic capacity. The...
Transduction01:16

Transduction

Among the three main modes of HGT—transformation, conjugation, and transduction—transduction is unique in that it is mediated by bacteriophages, or bacterial viruses.Transduction occurs in two ways. Generalized transduction occurs during the lytic cycle of a bacteriophage infection. In this process, bacteriophages infect bacterial cells, replicate within them, and ultimately cause cell lysis, releasing newly assembled virions. Occasionally, random fragments of the bacterial genome are...
In-vitro Mutagenesis01:16

In-vitro Mutagenesis

To learn more about the function of a gene, researchers can observe what happens when the gene is inactivated or “knocked out,” by creating genetically engineered knockout animals. Knockout mice have been particularly useful as models for human diseases such as cancer, Parkinson’s disease, and diabetes.
Frequency-dependent Selection01:21

Frequency-dependent Selection

When the fitness of a trait is influenced by how common it is (i.e., its frequency) relative to different traits within a population, this is referred to as frequency-dependent selection. Frequency-dependent selection may occur between species or within a single species. This type of selection can either be positive—with more common phenotypes having higher fitness—or negative, with rarer phenotypes conferring increased fitness.

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Butuanimides, Fatty Acid Synthesis-Inhibiting Antibiotics from Symbiotic Bacteria.

ACS chemical biology·2026
Same author

Telomeric amplicons of <i>SUL1</i> and Y' in yeast are generated by microhomology-mediated break induced replication occurring <i>in cis</i>.

bioRxiv : the preprint server for biology·2026
Same author

Short tandem gene duplications as potential agents of genetic memory.

mBio·2025
Same author

CsrA-Controlled Proteins Reveal New Dimensions of Acinetobacter baumannii Desiccation Tolerance.

Journal of bacteriology·2022
Same author

The symmetry spectrum in a hybridising, tropical group of rhododendrons.

The New phytologist·2022
Same author

Gene Duplication and Differential Expression of Flower Symmetry Genes in <i>Rhododendron</i> (Ericaceae).

Plants (Basel, Switzerland)·2021

Related Experiment Video

Updated: May 21, 2026

Identifying Amino Acid Overproducers Using Rare-Codon-Rich Markers
10:41

Identifying Amino Acid Overproducers Using Rare-Codon-Rich Markers

Published on: June 24, 2019

Exploiting a natural auxotrophy for genetic selection.

Elizabeth Ramage1, Larry Gallagher, Colin Manoil

  • 1Department of Genome Sciences, University of Washington, Seattle, Washington, USA.

Applied and Environmental Microbiology
|June 5, 2012
PubMed
Summary
This summary is machine-generated.

Researchers developed a new positive selection marker using the hisD gene for Francisella species. This advancement aids in genetic manipulation and the creation of a simplified growth medium for Francisella novicida.

More Related Videos

Mutagenesis and Functional Selection Protocols for Directed Evolution of Proteins in E. coli
09:01

Mutagenesis and Functional Selection Protocols for Directed Evolution of Proteins in E. coli

Published on: March 16, 2011

Generation of Enterobacter sp. YSU Auxotrophs Using Transposon Mutagenesis
13:31

Generation of Enterobacter sp. YSU Auxotrophs Using Transposon Mutagenesis

Published on: October 31, 2014

Related Experiment Videos

Last Updated: May 21, 2026

Identifying Amino Acid Overproducers Using Rare-Codon-Rich Markers
10:41

Identifying Amino Acid Overproducers Using Rare-Codon-Rich Markers

Published on: June 24, 2019

Mutagenesis and Functional Selection Protocols for Directed Evolution of Proteins in E. coli
09:01

Mutagenesis and Functional Selection Protocols for Directed Evolution of Proteins in E. coli

Published on: March 16, 2011

Generation of Enterobacter sp. YSU Auxotrophs Using Transposon Mutagenesis
13:31

Generation of Enterobacter sp. YSU Auxotrophs Using Transposon Mutagenesis

Published on: October 31, 2014

Area of Science:

  • Microbiology
  • Genetics

Background:

  • Francisella species exhibit natural histidine auxotrophy, requiring external histidine for growth.
  • Genetic manipulation of Francisella is crucial for understanding virulence and developing countermeasures.

Purpose of the Study:

  • To develop a novel positive selection marker for Francisella species.
  • To create a tool for genetic manipulation in both attenuated and virulent Francisella strains.
  • To formulate a simplified defined growth medium for Francisella novicida.

Main Methods:

  • Exploited the histidine auxotrophy of Francisella.
  • Utilized the Escherichia coli hisD gene (encoding histidinol dehydrogenase) as a positive selection marker.
  • Constructed a shuttle plasmid (pBR103) for cloning PCR fragments.
  • Developed a simplified defined growth medium.

Main Results:

  • Successfully developed hisD as a functional positive selection marker in Francisella.
  • The shuttle plasmid pBR103 demonstrated replication in both attenuated and virulent Francisella strains.
  • A simplified defined growth medium for Francisella novicida was formulated.

Conclusions:

  • The hisD gene serves as an effective positive selection marker for Francisella genetics.
  • The developed shuttle plasmid facilitates genetic engineering in diverse Francisella strains.
  • The simplified medium streamlines growth conditions for Francisella novicida research.