Related Experiment Video
Updated: Dec 17, 2025

Exploring X Chromosomal Aberrations in Ovarian Cells by Using Fluorescence In Situ Hybridization
Published on: April 7, 2023
Fertile male tortoiseshell cat with true chimerism 38,XY/38,XY
Monika Bugno-Poniewierska1, Barbara Kij1, Wojciech Witarski2
1Department of Animal Reproduction, Anatomy and Genomics, University of Agriculture in Krakow, Krakow, Poland.
Abstract:
The tortoiseshell coat colour is characteristic to female cats, and its occurrence in tomcats is very rare and associated with chromosome abnormalities (additional copy of X chromosome). The aim of this study was identification of the genetic basis of a case of tortoiseshell colour in a fertile Maine coon tomcat. Cytogenetic and molecular genetic studies were carried out with painting molecular probes (WCPP) specific to the X and Y sex chromosomes as well as a DNA microsatellite panel for the parentage verification of cats. Cytogenetic analysis revealed only a single set of sex chromosomes typical for male - 38,XY. The results of the microsatellite polymorphism obtained from DNA showed three alleles in locus FCA201 and four alleles in loci FCA149 and FCA441 in different tissues (blood, hair roots and testicles). Based on these results, the case was diagnosed as a true chimerism 38,XY/38,XY. To the best of our knowledge, this is the first case of a 38,XY/38,XY chimera diagnosed in cats, confirmed by genetic analysis.
Related Concept Videos
X-Inactivation
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...
Trihybrid Crosses
Some of Mendel’s crosses examined three pairs of contrasting characteristics. Such a cross is called a trihybrid cross. A trihybrid cross is a combination of three individual monohybrid crosses. For example, plant height (tall vs. short), seed shape (round vs. wrinkled), and seed color (yellow vs. green).
The F1 generation plants of a trihybrid cross are heterozygous for all three traits and produce eight gametes. Upon self-fertilization, these gametes have an equal...
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...
Crossing Over
The homologous pairs of sister chromosomes—one from the maternal and one from the paternal genome—then begin to align alongside each other lengthwise, matching corresponding DNA positions in a process...
The Y Chromosome Determines Maleness
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....

