Strain Name:
Stock Number:
Citation ID:
Other Names:
XY*, Y*; "Y star"

Gene Information

Transposon: Y(IsXPAR;Y)Ei (Mus musculus (mouse))
Name: Chr Y, insertion of X PAR region to Y PAR region, Eva Eicher; Chr Y, insertion of X pseudoautosomal region to Y pseudoautosomal region, Eicher
Synonyms: Y star, T8Ei, T(XA1?;InY)8Ei, Y*
Chromosome: Y
Alteration at locus: Insertion
Monarch Initiative (Disease and Phenotype Associations): MGI:5300493
Genetic Alterations
B6Ei.LT-Y(IsXPAR;Y)Ei/EiJ (JAX Strain #002021) backcrossed for 14 generations to C57BL/6J. The mutation was described in a preliminary fashion in Eicher, E M., "Primary sex-determining genes in mice." (1982). Faculty Research 1980 - 1989. 386, then investigated further in PMID:1743079.
ES Cell Line

Homozygous: Phenotypes extensively reported in publications cited. The model is useful for the study of any sex difference in a mouse phenotype.

MeSH Terms
  • Animals
  • Crossing Over, Genetic
  • Female
  • Gene Rearrangement
  • Male
  • Mice
  • Mice, Inbred C3H
  • X Chromosome
  • Y Chromosome
  • Base Sequence
  • Blotting, Southern
  • Centromere
  • Fertility/genetics
  • Fluorescence
  • Heterochromatin
  • Karyotyping
  • Mice, Inbred Strains
  • Mitosis/genetics
  • Molecular Sequence Data
  • Nucleic Acid Hybridization
  • Recombination, Genetic/genetics
  • Sex Chromosome Aberrations/genetics
  • Cloning, Molecular
  • DNA/isolation & purification
  • DNA Probes
  • Electrophoresis, Agar Gel
  • Mice, Inbred C57BL
  • Multigene Family
  • Restriction Mapping
  • Retroviridae/genetics
  • Sequence Homology, Nucleic Acid
  • Species Specificity
  • Central Nervous System/abnormalities
  • Central Nervous System/cytology
  • Central Nervous System/metabolism
  • Gene Deletion
  • Gene Dosage/genetics
  • Gene Expression Regulation, Developmental/genetics
  • Genes, sry/genetics
  • Mice, Knockout
  • Mutation/genetics
  • Neural Tube/abnormalities
  • Neural Tube/cytology
  • Neural Tube/metabolism
  • Neural Tube Defects/genetics
  • Neural Tube Defects/metabolism
  • Neural Tube Defects/physiopathology
  • Sex Characteristics
  • Sex Determination Processes
  • Sex Differentiation/genetics
  • Tumor Suppressor Protein p53/genetics
  • X Chromosome/genetics
  • X Chromosome Inactivation/genetics
  • Y Chromosome/genetics
  • Gene Expression Regulation/physiology
  • Genotype
  • Gonadal Steroid Hormones/metabolism
  • Sex Factors
  • Biomarkers/blood
  • Cholesterol, HDL/blood
  • Gene Dosage
  • Hypercholesterolemia/blood
  • Hypercholesterolemia/genetics
  • Orchiectomy
  • Ovariectomy
  • Ovary/metabolism
  • Phenotype
  • Testis/metabolism
  • Up-Regulation
  • Calcium/metabolism
  • Mitochondrial Membrane Transport Proteins
  • Myocardial Infarction/genetics
  • Myocardial Infarction/pathology
  • Myocardial Reperfusion Injury/genetics
  • Myocardial Reperfusion Injury/prevention & control
  • Adiposity/genetics
  • Body Composition/genetics
  • Body Temperature/genetics
  • Body Weight/genetics
  • Crosses, Genetic
  • Diet, High-Fat/adverse effects
  • Energy Metabolism/genetics
  • Glucose/metabolism
  • Metabolism/genetics
  • Models, Genetic
  • Sex Chromosome Aberrations
  • Adiposity/physiology
  • Diet, High-Fat
  • Gonadal Hormones/metabolism
  • Gonads/cytology
  • Gonads/metabolism
  • Insulin/blood
  • Lipid Metabolism/genetics
  • Lipids/blood
  • Obesity/genetics
  • Weight Gain/genetics
  • X Chromosome/physiology
  • Y Chromosome/physiology
  • Amygdala/metabolism
  • Behavior, Animal/physiology
  • Child
  • Gene Expression Regulation/genetics
  • Genes, X-Linked
  • Humans
  • Social Behavior
  • Turner Syndrome/blood
  • Turner Syndrome/genetics
  • Vasopressins/genetics
  • Vasopressins/metabolism
  • Disease Models, Animal
  • Sex Chromosomes/genetics
  • Aneuploidy
  • Brain/embryology
  • Brain/metabolism
  • Chromosome Breakpoints
  • Gene Expression Profiling
  • Gene Expression Regulation, Developmental
  • Genes, X-Linked/genetics
  • Genes, Y-Linked/genetics
  • Gonadal Steroid Hormones/genetics
  • Mice, Mutant Strains
  • Oligonucleotide Array Sequence Analysis
  • Transcription, Genetic
  • Translocation, Genetic
  • Aggression/physiology
  • Aromatase/biosynthesis
  • Copulation/physiology
  • Ejaculation/physiology
  • Estrogen Receptor alpha/biosynthesis
  • Genitalia, Male/anatomy & histology
  • Immunohistochemistry
  • Radioimmunoassay
  • Real-Time Polymerase Chain Reaction
  • Receptors, Androgen/biosynthesis
  • Septum of Brain/metabolism
  • Sexual Behavior, Animal/physiology
  • Vasopressins/blood
  • Behavior, Animal
  • Mice, Transgenic
  • Play and Playthings
  • Sex Chromosomes
  • Social Environment
Strain Development
Jackson Strain #002021 was backcrossed exclusively to C57BL/6J females for >14 generations. The Y* chromosome is backcrossed from the father.
Suggested Control Mice
Wild-type littermates
  • Apoptosis
  • Cancer
  • Cardiovascular
  • Cell Biology
  • Dermatology
  • Developmental Biology
  • Diabetes
  • Endocrine Deficiency
  • Hematology
  • Immunology and Inflammation
  • Internal_Organ
  • Metabolism
  • Models for Human Disease
  • Neurobiology
  • Obesity
  • Reproduction
  • Research Tools
  • Sensorineural
  • Virology
Arthur Arnold, Ph.D., University of California, Los Angeles.
Primary Reference

Burgoyne PS, Mahadevaiah SK, Perry J, Palmer SJ, Ashworth A. The Y*rearrangement in mice: new insights into a perplexing PAR. Cytogenet Cell Genet. 1998;80(1-4):37-40. (Medline PMID: 9678332)

Burgoyne PS, Arnold AP. A primer on the use of mouse models for identifyingdirect sex chromosome effects that cause sex differences in non-gonadal tissues. Biol Sex Differ. 2016 Dec 13;7:68. doi: 10.1186/s13293-016-0115-5. eCollection2016. Review. (Medline PMID: 27999654)

Eicher EM, Hale DW, Hunt PA, Lee BK, Tucker PK, King TR, Eppig JT, WashburnLL. The mouse Y* chromosome involves a complex rearrangement, includinginterstitial positioning of the pseudoautosomal region. Cytogenet Cell Genet.1991;57(4):221-30. (Medline PMID: 1743079)

Eicher EM, Hutchison KW, Phillips SJ, Tucker PK, Lee BK. A repeated segment onthe mouse Y chromosome is composed of retroviral-related, Y-enriched andY-specific sequences. Genetics. 1989 May;122(1):181-92. (Medline PMID: 2731728)

Chen X, Watkins R, Delot E, Reliene R, Schiestl RH, Burgoyne PS, Arnold AP.Sex difference in neural tube defects in p53-null mice is caused by differencesin the complement of X not Y genes. Dev Neurobiol. 2008 Feb 1;68(2):265-73.(Medline PMID: 18004765)

Arnold AP, Reue K, Eghbali M, Vilain E, Chen X, Ghahramani N, Itoh Y, Li J,Link JC, Ngun T, Williams-Burris SM. The importance of having two X chromosomes. Philos Trans R Soc Lond B Biol Sci. 2016 Feb 19;371(1688):20150113. doi:10.1098/rstb.2015.0113. Epub 2016 Feb 1. Review. (Medline PMID: 26833834)

Link JC, Chen X, Prien C, Borja MS, Hammerson B, Oda MN, Arnold AP, Reue K.Increased high-density lipoprotein cholesterol levels in mice with XX versus XYsex chromosomes. Arterioscler Thromb Vasc Biol. 2015 Aug;35(8):1778-86. doi:10.1161/ATVBAHA.115.305460. Epub 2015 Jun 25. (Medline PMID: 26112012)

Li J, Chen X, McClusky R, Ruiz-Sundstrom M, Itoh Y, Umar S, Arnold AP, EghbaliM. The number of X chromosomes influences protection from cardiacischaemia/reperfusion injury in mice: one X is better than two. Cardiovasc Res.2014 Jun 1;102(3):375-84. doi: 10.1093/cvr/cvu064. Epub 2014 Mar 19. (Medline PMID: 24654234)

Chen X, McClusky R, Itoh Y, Reue K, Arnold AP. X and Y chromosome complementinfluence adiposity and metabolism in mice. Endocrinology. 2013Mar;154(3):1092-104. doi: 10.1210/en.2012-2098. Epub 2013 Feb 8. (Medline PMID: 23397033)

Chen X, McClusky R, Chen J, Beaven SW, Tontonoz P, Arnold AP, Reue K. Thenumber of x chromosomes causes sex differences in adiposity in mice. PLoS Genet. 2012;8(5):e1002709. doi: 10.1371/journal.pgen.1002709. Epub 2012 May 10. (Medline PMID: 22589744)

Chen X, Watkins R, Delot E, Reliene R, Schiestl RH, Burgoyne PS, Arnold AP.Sex difference in neural tube defects in p53-null mice is caused by differencesin the complement of X not Y genes. Dev Neurobiol. 2008 Feb 1;68(2):265-73.(Medline PMID: 18004765)

Cox KH, Quinnies KM, Eschendroeder A, Didrick PM, Eugster EA, Rissman EF.Number of X-chromosome genes influences social behavior and vasopressin geneexpression in mice. Psychoneuroendocrinology. 2015 Jan;51:271-81. doi:10.1016/j.psyneuen.2014.10.010. Epub 2014 Oct 23. (Medline PMID: 25462900)

Cox KH, Bonthuis PJ, Rissman EF. Mouse model systems to study sex chromosomegenes and behavior: relevance to humans. Front Neuroendocrinol. 2014Oct;35(4):405-19. doi: 10.1016/j.yfrne.2013.12.004. Epub 2014 Jan 2. Review.(Medline PMID: 24388960)

Wolstenholme JT, Rissman EF, Bekiranov S. Sexual differentiation in thedeveloping mouse brain: contributions of sex chromosome genes. Genes Brain Behav.2013 Mar;12(2):166-80. doi: 10.1111/gbb.12010. Epub 2013 Jan 10. (Medline PMID: 23210685)

Bonthuis PJ, Cox KH, Rissman EF. X-chromosome dosage affects male sexualbehavior. Horm Behav. 2012 Apr;61(4):565-72. doi: 10.1016/j.yhbeh.2012.02.003.Epub 2012 Feb 10. (Medline PMID: 22349083)

Cox KH, Rissman EF. Sex differences in juvenile mouse social behavior areinfluenced by sex chromosomes and social context. Genes Brain Behav. 2011Jun;10(4):465-72. doi: 10.1111/j.1601-183X.2011.00688.x. Epub 2011 Apr 19. (Medline PMID: 21414140)

Colony and Husbandry Information

Colony Surveillance Program and Current Health Reports

Mice recovered from a cryo-archive will have health surveillance performed on recipient females. Health reports will be provided prior to shipment. If you require additional health status information, please email .
Coat Color
MMRRC Breeding System
Breeding Scheme(s)
XY* males crossed with C57BL/6J - Jackson Strain #000664 (or first-generation XX daughters of #000664 bred at UCLA) each generation.
N14 (C57BL/6J)
Overall Breeding Performance
NOTE: "Hemizygote" as used here refers to males carrying a mutation on the X Chromosome or mice of either sex carrying an inserted transgene with no homologous allele on the other chromosome.
Viability and Fertility: Female Male Comments
Homozygotes are viable: Yes Yes
Homozygotes are fertile: N/A N/A
Hetero/Hemizygotes are fertile: N/A N/A
Age Reproductive Decline: Undetermined Greater than 12 months
Bred to Homozygosity
Average litter size
Recommended wean age
3-4 weeks
Average Pups Weaned

Order Request Information

Limited quantities of breeder mice (recovered litter) are available from a cryoarchive; recovered litter usually available to ship in 3 to 4 months.

Distribution of this strain requires submission of the MMRRC Conditions of Use (COU). A link to the COU web form will be provided via email after an order has been placed; the form should be completed then or the email forwarded to your institutional official for completion.

Additional charges may apply for any special requests. Shipping costs are in addition to the basic distribution/resuscitation fees. Information on shipping costs and any additional charges will be provided by the supplying MMRRC facility.

Click button to Request this one strain. (Use the MMRRC Catalog Search to request more than one strain.)
MMRRC Item # Description Distribution Fee / Unit (US $) Units Notes
043694-UCD-EMBRYO Cryo-preserved embryos $1,038.00 / $1,549.67
Non-Profit / For-Profit
Aliquot Approximate quantity3 : 20-40 embryos / aliquot
043694-UCD-SPERM Cryo-preserved spermatozoa $546.25 / $871.90
Non-Profit / For-Profit
Aliquot Approximate quantity2
043694-UCD-RESUS Litter recovered from cryo-archive $3,033.00 / $6,017.01
Non-Profit / For-Profit
Litter Recovered litter1; additional fees for any special requests.

1 The distribution fee covers the expense of resuscitating mice from the cryo-archive; you will receive the resulting litter. The litter will contain at minimum one mutant carrier; the actual number of animals and the gender and genotype ratios will vary. (Typically, multiple breeder pairs can be established from the recovered litter.) Prior to shipment, the MMRRC will provide information about the animals recovered. If you anticipate or find that you need to request specific genotypes, genders or quantities of mice in excess of what is likely from a resuscitated litter, you may discuss available options and pricing with the supplying MMRRC facility.

2 An aliquot is one straw or vial with sufficient sperm to recover at least one litter of mice, as per provided protocols, when performed at the MMRRC facility. The MMRRC makes no guarantee concerning the success of these procedures when performed outside the MMRRC facilities.

3 An aliquot contains a sufficient number of embryos (in one or more vials and based on the transfer success rate of the MMRRC facility) to transfer to at least two recipients. The MMRRC makes no guarantee concerning embryo transfer success experienced in the recipient investigator's laboratory. Neither gender nor genotype ratios are guaranteed.

To request material from the MMRRC: Please fill out our on-line request form (accessible from the catalog search results page, or click the Request this Strain button in the fees section). If you have questions or need assistance completing this form, you may call Customer Service at (800) 910-2291 (in USA or Canada) or (530) 757-5710 (international calls). Before you call, please have with you: the MMRRC item number, quantity needed, Bill-to and Ship-to contact information.