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

Cis-regulatory Sequences02:02

Cis-regulatory Sequences

9.9K
Cis-regulatory sequences are short fragments of non-coding DNA that are present on the same chromosomes as the genes that they regulate. These fragments serve as binding sites for transcriptional regulators, proteins that are responsible for controlling gene transcription and differential gene expression across cell types in eukaryotes. Cis-regulatory sequences can be close to the gene of interest or thousands of bases away in the DNA sequence; however, those sequences that are further away are...
9.9K
Types of Selection01:46

Types of Selection

40.5K
Natural selection influences the frequencies of particular alleles and phenotypes within populations in several different ways. Primarily, natural selection can be directional, stabilizing, or disruptive. Directional selection favors one extreme trait and shifts the population towards that phenotype while selecting against individuals displaying alternate traits. Stabilizing selection favors an intermediate trait with a narrow range of variation. Deviation from the optimal phenotype towards an...
40.5K
The Y Chromosome Determines Maleness02:19

The Y Chromosome Determines Maleness

6.6K
The Y chromosome is a sex chromosome found in several vertebrates and mammals, including humans. In addition to 22 pairs of autosomes, the human males have one X chromosome and one Y chromosome. In these organisms, the presence or absence of the Y chromosome determines the development of male traits.
Evolution
Around 300 million years ago, the two sex chromosomes diverged from two identical autosomal chromosomes. Over time, the Y chromosome has lost most of its genes, shrinking in size....
6.6K
The Ratio of X Chromosome to Autosomes02:45

The Ratio of X Chromosome to Autosomes

8.5K
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...
8.5K
Dosage Compensation02:50

Dosage Compensation

6.2K
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...
6.2K
Frequency-dependent Selection01:21

Frequency-dependent Selection

22.0K
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.
22.0K

You might also read

Related Articles

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

Sort by
Same author

High-resolution global recombination mapping in C. elegans reveals sexual dimorphisms shaped by meiotic chromosomal features and structures.

PLoS genetics·2026
Same author

Adaptation across an extreme elevational gradient in Andean leaf-eared mice, the world's highest-dwelling mammal.

Science (New York, N.Y.)·2026
Same author

A Y-linked duplication of anti-Mullerian hormone is the sex determination gene in threespine stickleback.

PLoS genetics·2025
Same author

Single cell RNA-sequencing reveals no evidence for meiotic sex chromosome inactivation in the threespine stickleback fish.

PLoS genetics·2025
Same author

A Y-linked duplication of anti-Mullerian hormone is the sex determination gene in threespine stickleback.

bioRxiv : the preprint server for biology·2025
Same author

Avid lysosomal acidification in fibroblasts of the Mediterranean mouse <i>Mus spretus</i>.

bioRxiv : the preprint server for biology·2025

Related Experiment Video

Updated: Jul 4, 2025

Microinjection for Transgenesis and Genome Editing in Threespine Sticklebacks
08:51

Microinjection for Transgenesis and Genome Editing in Threespine Sticklebacks

Published on: May 13, 2016

14.0K

Positive Selection Drives cis-regulatory Evolution Across the Threespine Stickleback Y Chromosome.

Daniel E Shaw1, Alice Shanfelter Naftaly1, Michael A White1

  • 1Department of Genetics, University of Georgia, Athens, GA 30602, USA.

Molecular Biology and Evolution
|February 2, 2024
PubMed
Summary

Gene expression on Y chromosomes rapidly evolves, with evidence suggesting positive selection drives regulatory changes. This rapid divergence may help mask deleterious mutations on the Y chromosome.

Keywords:
cis-regulatory elementspositive selectionsex chromosomesstickleback fish

More Related Videos

Dissection and Flat-mounting of the Threespine Stickleback Branchial Skeleton
08:02

Dissection and Flat-mounting of the Threespine Stickleback Branchial Skeleton

Published on: May 7, 2016

9.9K
Quantitative Comparison of cis-Regulatory Element CRE Activities in Transgenic Drosophila melanogaster
08:19

Quantitative Comparison of cis-Regulatory Element CRE Activities in Transgenic Drosophila melanogaster

Published on: December 19, 2011

11.8K

Related Experiment Videos

Last Updated: Jul 4, 2025

Microinjection for Transgenesis and Genome Editing in Threespine Sticklebacks
08:51

Microinjection for Transgenesis and Genome Editing in Threespine Sticklebacks

Published on: May 13, 2016

14.0K
Dissection and Flat-mounting of the Threespine Stickleback Branchial Skeleton
08:02

Dissection and Flat-mounting of the Threespine Stickleback Branchial Skeleton

Published on: May 7, 2016

9.9K
Quantitative Comparison of cis-Regulatory Element CRE Activities in Transgenic Drosophila melanogaster
08:19

Quantitative Comparison of cis-Regulatory Element CRE Activities in Transgenic Drosophila melanogaster

Published on: December 19, 2011

11.8K

Area of Science:

  • Evolutionary genetics
  • Sex chromosome evolution

Background:

  • Allele-specific gene expression evolves rapidly on sex chromosomes.
  • Y chromosomes accumulate mutations over time, leading to gametolog expression loss relative to the X chromosome.
  • The drivers of Y chromosome expression evolution (selective interference vs. positive selection) remain unclear.

Purpose of the Study:

  • To investigate the evolutionary dynamics of cis-regulatory sequences on Y chromosomes.
  • To determine if positive selection favors down-regulation of Y-linked genes with deleterious mutations.
  • To use the threespine stickleback as a model system due to its intermediate X-Y divergence.

Main Methods:

  • Analysis of substitution rates and polymorphism in Y-linked cis-regulatory regions.
  • Comparison of Y-chromosome regulatory regions with non-functional sites (intergenic, synonymous).
  • Correlation of Y-chromosome regulatory divergence with X-biased gametolog expression.

Main Results:

  • Putative enhancer regions on the Y chromosome show elevated substitution rates and decreased polymorphism.
  • These patterns suggest positive selection acting on Y-linked cis-regulatory regions.
  • Y-chromosome regulatory divergence correlates with X-biased gene expression, indicating selection favors Y expression loss.

Conclusions:

  • Y-linked cis-regulatory regions show signs of positive selection soon after recombination suppression.
  • Rapid divergence of regulatory regions may be selected to mask deleterious mutations on the Y chromosome.
  • This study provides evidence for selection driving Y chromosome gene expression evolution.