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

The Ratio of X Chromosome to Autosomes02:45

The Ratio of X Chromosome to Autosomes

11.5K
In most organisms, sex is determined by the ratio of X and Y chromosomes. However, in some organisms, such as Drosophila and C.elegans, sex is determined by the ratio of the number of X chromosomes to the number of sets of autosomes. The Y chromosome in Drosophila is active but does not determine sex. It contains genes responsible for the production of sperms in adult flies.  
Normal male Drosophila has a ratio of one X chromosome to two sets of autosomes. In contrast, normal female...
11.5K
Dosage Compensation02:50

Dosage Compensation

6.3K
In animals, gender is determined by the number and type of sex chromosome. For example, human females have two X chromosomes, and males have one X and one Y chromosome, whereas C.elegans with one X chromosome is a male, and the one with two X chromosomes is a hermaphrodite.
In addition to sexual development, the X chromosome has genes involved in autosomal functions such as brain development and the immune system. Therefore, males and females with  distinct numbers of X chromosomes will...
6.3K
Background and Environment Affect Phenotype02:27

Background and Environment Affect Phenotype

5.8K
Although the genetic makeup of an organism plays a major role in determining the phenotype, there are also several environmental factors, such as temperature, oxygen availability, presence of mutagens, that can alter an organism’s phenotype.
An example of how genetic background affects phenotype can be seen in horses. The Extension gene in horses is responsible for their coat color. A wild-type gene (EE) produces black pigment in the coat, while a mutant gene (ee) produces red pigment. A...
5.8K
Frequency-dependent Selection01:21

Frequency-dependent Selection

20.1K
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.
20.1K
Mate Choice01:20

Mate Choice

8.3K
Mate choice—the decision about whom to mate with—is a type of natural selection, since animals must reproduce to pass down their genes. Mate choice is also called intersexual selection because the behavior occurs between the sexes.
8.3K
Genetic Variation01:25

Genetic Variation

1.7K
Genetic variation is the diversity in DNA sequences found among individuals of the same species. This diversity is crucial for a species' survival because it helps organisms adapt to environmental changes. Genetic variation begins with fertilization, where an egg and sperm cell merge. Each of these cells carries 23 chromosomes, up to 46 in the fertilized egg. Chromosomes are long DNA strands that contain genes, the basic units of heredity.
Genes exist in different versions called alleles,...
1.7K

You might also read

Related Articles

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

Sort by
Same author

Erratum: "First experiments with ultrashort, circularly polarized soft x-ray pulses at FLASH2" [Struct. Dyn. <b>12</b>, 034301 (2025)].

Structural dynamics (Melville, N.Y.)·2026
Same author

First experiments with ultrashort, circularly polarized soft x-ray pulses at FLASH2.

Structural dynamics (Melville, N.Y.)·2025
Same author

Simultaneous mapping of the ultrafast time and fluence dependence of the laser-induced insulator-to-metal transition in magnetite.

Structural dynamics (Melville, N.Y.)·2025
Same author

Cure of urethro-rectal fistula secondary to a road traffic accident by perineal approach with gracilis flap interposition: A case report.

International journal of surgery case reports·2024
Same author

Cavernous haemangioma and mid trimester pregnancy loss leading to severe haemorrhage and hysterectomy: a case report and review of literature.

Facts, views & vision in ObGyn·2023
Same author

Endometrial biopsy under direct hysteroscopic visualisation versus blind endometrial sampling for the diagnosis of endometrial hyperplasia and cancer: Systematic review and meta-analysis.

Facts, views & vision in ObGyn·2022

Related Experiment Video

Updated: May 4, 2026

Induction and Evaluation of Inbreeding Crosses Using the Ant, Vollenhovia Emeryi
06:44

Induction and Evaluation of Inbreeding Crosses Using the Ant, Vollenhovia Emeryi

Published on: October 5, 2018

7.1K

Sex determination in insects: variations on a common theme.

D Bopp1, G Saccone, M Beye

  • 1Institute of Molecular Life Sciences, University of Zurich, Zurich, Switzerland.

Sexual Development : Genetics, Molecular Biology, Evolution, Endocrinology, Embryology, and Pathology of Sex Determination and Differentiation
|December 17, 2013
PubMed
Summary

The conserved transformer (tra) gene acts as a key switch in insect sex determination, with upstream and downstream pathways diverging during evolution. This conserved core ensures reliable sex fate transduction.

More Related Videos

Author Spotlight: Whole-Mount Fluorescence In Situ Hybridization to Study Spermatogenesis in the Anopheles Mosquito
05:31

Author Spotlight: Whole-Mount Fluorescence In Situ Hybridization to Study Spermatogenesis in the Anopheles Mosquito

Published on: May 26, 2023

4.8K
Assessing Differences in Sperm Competitive Ability in Drosophila
09:34

Assessing Differences in Sperm Competitive Ability in Drosophila

Published on: August 22, 2013

14.2K

Related Experiment Videos

Last Updated: May 4, 2026

Induction and Evaluation of Inbreeding Crosses Using the Ant, Vollenhovia Emeryi
06:44

Induction and Evaluation of Inbreeding Crosses Using the Ant, Vollenhovia Emeryi

Published on: October 5, 2018

7.1K
Author Spotlight: Whole-Mount Fluorescence In Situ Hybridization to Study Spermatogenesis in the Anopheles Mosquito
05:31

Author Spotlight: Whole-Mount Fluorescence In Situ Hybridization to Study Spermatogenesis in the Anopheles Mosquito

Published on: May 26, 2023

4.8K
Assessing Differences in Sperm Competitive Ability in Drosophila
09:34

Assessing Differences in Sperm Competitive Ability in Drosophila

Published on: August 22, 2013

14.2K

Area of Science:

  • Developmental Biology
  • Evolutionary Genetics
  • Insect Biology

Background:

  • Sex determination pathways in holometabolous insects show conserved signal-relaying mechanisms.
  • The transformer (tra) gene functions as a central binary switch, regulating downstream doublesex (dsx) gene expression.
  • Maternal activity typically activates zygotic tra for female development, with male-determining signals evolving to prevent this.

Purpose of the Study:

  • To investigate the conserved elements and evolutionary divergence within insect sex-determining pathways.
  • To understand how different signals converge on the conserved transformer (tra) gene.
  • To explore the evolutionary plasticity of upstream and downstream components of sex determination.

Main Methods:

  • Comparative analysis of sex-determining genes across diverse holometabolous insect species.
  • Examination of the transformer (tra) gene's role as a conserved signal transducer.
  • Analysis of upstream signals and downstream effectors in relation to evolutionary changes.

Main Results:

  • The signal-relaying component, centered on the transformer (tra) gene, is highly conserved across studied insects.
  • Upstream instructive signals and downstream doublesex (dsx) effectors exhibit significant evolutionary divergence.
  • Maternal activation of zygotic tra is a common feature, with male-determining signals acting to inhibit it.

Conclusions:

  • The core mechanism of sex signal transduction via transformer (tra) is evolutionarily stable.
  • Evolutionary novelty in sex determination primarily arises in the upstream regulatory inputs and downstream developmental outputs.
  • This pattern of conserved core and divergent ends is likely a common feature of developmental signaling pathways.