Related Experiment Video
Updated: Aug 22, 2026

Combined DNA-RNA Fluorescent In situ Hybridization (FISH) to Study X Chromosome Inactivation in Differentiated Female Mouse Embryonic Stem Cells
Published on: June 14, 2014
A longitudinal study of X-inactivation ratio in human females
Ionel Sandovici1, Anna K Naumova, Mark Leppert
1Fels Institute for Cancer Research and Molecular Biology, Temple University School of Medicine, Philadelphia, PA 19140, USA.
Abstract:
We investigated the effect of aging on X chromosome inactivation by performing a longitudinal study in a population of 178 normal females. We examined X-inactivation ratios (fraction of cells with the same X chromosome active) in two sets of peripheral blood DNA samples collected about two decades apart. We observed a strong correlation between the ratios of individual females at the two time points and found no significant difference between the two sets of measurements. These observations indicate that aging, per se (as opposed to being "aged"), has little effect on X-inactivation. However, we also found that several females who were older than 60 years of age at the time of the first measurement acquired significant changes in the X-inactivation ratio. We speculate that, if X-inactivation skewing is a frequently acquired trait in older females, it is acquired as the result of a discontinuous or catastrophic process and is not the result of constant selection for or against hematopoietic stem cells with a particular X chromosome active.
More Related Videos
12:42Quick Fluorescent In Situ Hybridization Protocol for Xist RNA Combined with Immunofluorescence of Histone Modification in X-chromosome Inactivation
Published on: November 26, 2014
08:27A Non-random Mouse Model for Pharmacological Reactivation of Mecp2 on the Inactive X Chromosome
Published on: May 22, 2019
Related Concept Videos
X-inactivation
X-Inactivation
Inheritance of Chromatin Structures
Dosage Compensation
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 have...
The Ratio of X Chromosome to Autosomes
Normal male Drosophila has a ratio of one X chromosome to two sets of autosomes. In contrast, normal female Drosophila...
X and Y Chromosomes
The germline cells such as egg and sperm cells carry only half the number of chromosomes, i.e., 22 autosomes and one sex chromosome. All eggs have an X chromosome, while sperm cells can carry an X or...