Search research articles

ABOUT JoVE

Overview Leadership Blog JoVE Help Center

AUTHORS

Publishing Process Editorial Board Scope & Policies Peer Review FAQ Submit

LIBRARIANS

Testimonials Subscriptions Access Resources Library Advisory Board FAQ

RESEARCH

JoVE Journal Methods Collections JoVE Encyclopedia of Experiments Archive

EDUCATION

JoVE Core JoVE Business JoVE Science Education JoVE Lab Manual Faculty Resource Center Faculty Site

Terms & Conditions of Use

Related Concept Videos

Gene Duplication and Divergence

Gene Duplication and Divergence

The seminal work of Ohno in 1970 popularized the idea of gene duplication and divergence. DNA sequence comparison studies reveal that a large portion of the genes in bacteria, archaebacteria, and eukaryotes was generated by gene duplication and divergence, indicating its critical role in evolution.
The duplicated copies of the gene are called Paralogs. Paralogs with similar sequences and functions form a gene family. Across several species, a large number of gene families are characterized.

Polytene Chromosomes

Polytene Chromosomes

Polytene chromosomes are giant interphase chromosomes with several DNA strands placed side by side. They were discovered in the year 1881 by Balbiani in salivary glands, intestine, muscles, malpighian tubules, and hypoderm of larvae Chironomus plumosus. Hence, these are also called "Salivary gland chromosomes." These are found in insects of the order Diptera and Collembola; in certain organs of mammals; and synergids, antipodes of flowering plants. Polytene chromosomes are also regularly...

Polytene Chromosomes

Polytene Chromosomes

Polytene chromosomes are giant interphase chromosomes with several DNA strands placed side by side. They were discovered in the year 1881 by Balbiani in salivary glands, intestine, muscles, malpighian tubules, and hypoderm of larvae Chironomus plumosus. Hence, these are also called "Salivary gland chromosomes." These are found in insects of the order Diptera and Collembola; in certain organs of mammals; and synergids, antipodes of flowering plants. Polytene chromosomes are also regularly...

Synteny and Evolution

Synteny and Evolution

John H. Renwick first coined the term “synteny” in 1971, which refers to the genes present on the same chromosomes, even if they are not genetically linked. The species with common ancestry tend to show conserved syntenic regions. Therefore, the concept of synteny is nowadays used to describe the evolutionary relationship between species.
Around 80 million years ago, the human and mice lineages diverged from the common ancestor. During the course of evolution, the ancestral chromosome underwent...

Nondisjunction

Nondisjunction

During meiosis, chromosomes occasionally separate improperly. This occurs due to failure of homologous chromosome separation during meiosis I or failed sister chromatid separation during meiosis II. In some species, notably plants, nondisjunction can result in an organism with an entire additional set of chromosomes, which is called polyploidy. In humans, nondisjunction can occur during male or female gametogenesis and the resulting gametes possess one too many or one too few chromosomes.

Nondisjunction

Nondisjunction

Nondisjunction is the failure of homologous chromosomes or sister chromatids to separate correctly and move to the opposite poles of the cells. This produces daughter cells with abnormal chromosome numbers. Nondisjunction is common during anaphase I or anaphase II of meiosis. Mutations in synaptonemal complex proteins that attach homologous chromosomes increase the chances of nondisjunction in anaphase I of meiosis I. In contrast, mutations in topoisomerases and condensins that hold sister...

You might also read

Related Articles

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

Sort by

Same author

Unveiling climate transformations in the northwestern Caucasus: the Middle Holocene divergence of landscape evolution.

Scientific reports·2026

Same author

Detailed cytogenetic analysis of three duck species (the northern pintail, mallard, and common goldeneye) and karyotype evolution in the family Anatidae (Anseriformes, Aves).

Vavilovskii zhurnal genetiki i selektsii·2024

Same author

Human DNA from the oldest Eneolithic cemetery in Nalchik points the spread of farming from the Caucasus to the Eastern European steppes.

iScience·2024

Same author

Distortion of Population Statistics due to the Use of Different Methodological Approaches to the Construction of Genomic DNA Libraries.

Acta naturae·2023

Same author

Unusual congenital polydactyly in mini-pigs from the breeding group of the Institute of Cytology and Genetics (Novosibirsk, Russia).

Vavilovskii zhurnal genetiki i selektsii·2021

Same author

DIVERSITY OF SEX DETERMINING MECHANISMS IN RAY-FINNED FISHES (ACTINOPTERYGII).

Tsitologiia·2018

Search research articles

Related Experiment Video

Updated: Jun 6, 2026

Genome-wide Purification of Extrachromosomal Circular DNA from Eukaryotic Cells

Genome-wide Purification of Extrachromosomal Circular DNA from Eukaryotic Cells

Published on: April 4, 2016

[Supernumerary chromosomes, segmental duplications, and evolution].

V A Trifonov, P V Dement'eva, V R Beklemisheva

|November 11, 2010

Summary

Supernumerary chromosomes, like segmental duplications, act as autonomous genome elements. Their nonrandom distribution and evolutionary role in mammals are explored.

More Related Videos

Manipulation of Ploidy in Caenorhabditis elegans

Manipulation of Ploidy in Caenorhabditis elegans

Published on: March 15, 2018

Following the Dynamics of Structural Variants in Experimentally Evolved Populations

Following the Dynamics of Structural Variants in Experimentally Evolved Populations

Published on: February 3, 2023

Related Experiment Videos

Last Updated: Jun 6, 2026

Genome-wide Purification of Extrachromosomal Circular DNA from Eukaryotic Cells

Genome-wide Purification of Extrachromosomal Circular DNA from Eukaryotic Cells

Published on: April 4, 2016

Manipulation of Ploidy in Caenorhabditis elegans

Manipulation of Ploidy in Caenorhabditis elegans

Published on: March 15, 2018

Following the Dynamics of Structural Variants in Experimentally Evolved Populations

Following the Dynamics of Structural Variants in Experimentally Evolved Populations

Published on: February 3, 2023

Area of Science:

Genetics
Evolutionary Biology
Genomics

Context:

Supernumerary chromosomes, often termed B chromosomes, represent a unique class of genetic material.
Their autonomous nature and similarity to segmental duplications suggest a distinct evolutionary role.

Purpose:

To investigate the characteristics of supernumerary chromosomes as autonomous genome elements.
To discuss the potential role of B chromosomes in mammalian evolution.
To explore the reasons behind the nonrandom distribution of B chromosomes across different mammalian taxa.

Summary:

This study characterizes supernumerary chromosomes as independent genomic entities, drawing parallels with segmental duplications.
The research examines the evolutionary significance of B chromosomes and analyzes the factors contributing to their uneven distribution in mammalian species.

Impact:

Provides insights into the evolutionary dynamics of accessory chromosomes.
Enhances understanding of genome evolution and diversity in mammals.
Contributes to the field of population genetics and chromosome evolution studies.