Related Experiment Video

Updated: Jul 27, 2025

Dissection of the Auditory Bulla in Postnatal Mice: Isolation of the Middle Ear Bones and Histological Analysis
07:40

Dissection of the Auditory Bulla in Postnatal Mice: Isolation of the Middle Ear Bones and Histological Analysis

Published on: January 4, 2017

30.4K

Abnormal X-Chromosome Dosage Compensation as a Possible Cause of Early Developmental Failure in Mice: (X-chromosome

Nobuo Takagi1

  • 1Research Center for Molecular Genetics, Hokkaido University North 10, West 8, Kita-Ku, Sapporo 060, Japan.

Development, Growth & Differentiation
|June 7, 2023
PubMed

Insights

An extra maternal X chromosome (XM) harms early mouse development, preventing key structure formation. This occurs because two active maternal X chromosomes, unlike paternal ones (XP), inhibit trophectoderm differentiation.

Area of Science:

  • Developmental Biology
  • Genetics
  • Epigenetics

Background:

  • Maternal imprinting of the X chromosome is crucial in early mammalian development.
  • Preferential inactivation of the paternal X chromosome (XP) occurs in normal female embryos.
  • The role of extra X chromosomes in embryogenesis requires further elucidation.

Purpose of the Study:

  • To investigate the impact of an extra maternally derived X chromosome (XM) on early mouse embryogenesis.
  • To determine if maternal or paternal origin of an extra X chromosome differentially affects embryonic development.
  • To explore the underlying mechanisms of developmental failure caused by an extra XM.

Main Methods:

  • Cytogenetic analysis of mouse embryos with varying X chromosome complements.
  • Assessment of key developmental milestones, including ectoplacental cone and extra-embryonic ectoderm formation.
  • Investigation of X chromosome activity in trophectoderm and primitive endoderm.

Main Results:

  • An extra maternally derived X chromosome (XM) is detrimental to early mouse embryogenesis.
  • Embryos with an extra XM fail to form the ectoplacental cone and extra-embryonic ectoderm.
  • Cytogenetic studies indicate two active XM chromosomes in trophectoderm and possibly primitive endoderm, unlike XP.

Conclusions:

  • Two active maternal X chromosomes (XM) due to imprinting prevent trophectoderm differentiation.
  • Maternal origin of an extra X chromosome is critical for its detrimental effect.
  • This finding highlights the importance of X chromosome dosage and parental origin in embryonic development.

More Related Videos

A Non-random Mouse Model for Pharmacological Reactivation of Mecp2 on the Inactive X Chromosome08:27

A Non-random Mouse Model for Pharmacological Reactivation of Mecp2 on the Inactive X Chromosome

Published on: May 22, 2019

6.4K
Author Spotlight: Studying the Impact of Maternal Dietary Deficiencies on Long-Term Offspring Health Outcomes03:19

Author Spotlight: Studying the Impact of Maternal Dietary Deficiencies on Long-Term Offspring Health Outcomes

Published on: June 28, 2024

466

Related Concept Videos

Dosage Compensation02:50

Dosage Compensation

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
X-Inactivation01:58

X-Inactivation

The human X chromosome contains over ten times the number of genes as in the Y chromosome. Since males have only one X chromosome, and females have two, one might expect females to produce twice as many of the proteins, with undesirable results.
38.8K
Sex-linked Disorders01:43

Sex-linked Disorders

Like autosomes, sex chromosomes contain a variety of genes necessary for normal body function. When a mutation in one of these genes results in biological deficits, the disorder is considered sex-linked.
102.4K
Nondisjunction01:29

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.
75.9K
The Ratio of X Chromosome to Autosomes02:45

The Ratio of X Chromosome to Autosomes

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...
8.6K
X-linked Traits01:19

X-linked Traits

In most mammalian species, females have two X sex chromosomes and males have an X and Y. As a result, mutations on the X chromosome in females may be masked by the presence of a normal allele on the second X. In contrast, a mutation on the X chromosome in males more often causes observable biological defects, as there is no normal X to compensate. Trait variations arising from mutations on the X chromosome are called “X-linked”.
55.1K