Pseudoautosomal Inheritance

Abstract

Traits encoded by genes on the X‐ and Y‐chromosomes are generally inherited in a specific manner, referred to as sex‐linked. Females receive alleles from their parent's X‐chromosomes, whereas males receive X‐encoded genes from their mother and Y‐encoded genes from their father. However, a small subset of genes on the X‐ and Y‐chromosomes exhibit a pattern of inheritance that is not sex‐linked. That is, genes on the Y‐chromosome are sometimes passed to daughters, and genes on the X‐chromosome are sometimes passed from fathers to their sons. This is possible because the X‐ and Y‐chromosomes share regions of sequence identity, and these regions undergo recombination during male meiosis. Therefore sequences can be transferred from the X to the Y, and vice versa. The resulting transmission pattern resembles that which is seen for sequences on autosomes, and is referred to as pseudoautosomal inheritance.

Key concepts:

  • The X‐ and Y‐chromosomes contain regions of sequence identity at the ends of their respective short and long arms.

  • Recombination takes place in male meiosis between the X and Y within these regions of DNA sequence identity.

  • Traditional patterns of sex‐linked inheritance are sometimes not observed for alleles in these regions of X–Y sequence identity.

  • The pattern of inheritance observed for alleles in the X–Y identical regions is referred to as pseudoautosomal inheritance, because it resembles the pattern seen for alleles located on autosomes. The areas of sequence identity on the X and Y are thus referred to as the pseudoautosomal regions.

  • The likelihood of observing pseudoautosomal inheritance for a given allele depends on its location within the pseudoautosomal region: the more distal a locus is, the more likely it will demonstrate pseudoautosomal inheritance.

Keywords: sex chromosomes; pseudoautosomal; recombination

Figure 1.

Pseudoautosomal inheritance of X and Y alleles. The lightly shaded areas represent the identical sequences on the X and Y short arms that comprise the pseudoautosomal region. It is within this region that recombination takes place between the X and Y. No recombination occurs between X‐ and Y‐specific sequences, represented by solid green and blue bars, respectively. The A/a alleles demonstrate pseudoautosomal inheritance, whereas the B/b alleles show sex‐linked inheritance.

Figure 2.

Pseudoautosomal inheritance of XE7 alleles. The figure shows restriction fragment length polymorphisms (RFLPs) at the pseudoautosomal XE7 locus in a three‐generation family. Individuals III‐4 and III‐10 exhibit pseudoautosomal inheritance as a result of exchange of X and Y alleles in the father (II‐1). Reproduced with permission from Ellison et al..

close

References

Belin V, Cusin V, Viot G et al. (1998) SHOX mutations in dyschondrosteosis (Leri‐Weill syndrome). Nature Genetics 19: 67–69.

Burgoyne PS (1982) Genetic homology and crossing over in the X and Y chromosomes of mammals. Human Genetics 61: 85–90.

Dal Zotto L, Quaderi NA, Elliot R et al. (1998) The mouse Mid1 gene: implications for the pathogenesis of Opitz syndrome and the evolution of the mammalian pseudoautosomal region. Human Molecular Genetics 7: 488–499.

Ellis NA, Ye TZ, Patton S et al. (1994) Cloning of PBDX, an MIC2‐related gene that spans the pseudoautosomal boundary on chromosome Xp. Nature Genetics 6: 394–400.

Ellison J, Passage M, Yu L‐C, Yen P and Shapiro L (1992) Directed isolation of human genes that escape X inactivation. Somatic Cell and Molecular Genetics 18: 259–268.

Ellison JW, Wardak Z, Young MF et al. (1997) PHOG, a candidate gene for involvement in the short stature of Turner syndrome. Human Molecular Genetics 6: 1341–1347.

Keitges E, Rivest M, Siniscalco M and Gartler SM (1985) X‐linkage of steroid sulfatase in the mouse is evidence for a functional Y‐linked allele. Nature 315: 226–227.

Palmer S, Perry J, Kipling D and Ashworth A (1997) A gene spans the pseudoautosomal boundary in mice. Proceedings of the National Academy of Sciences of the USA 94: 12030–12035.

Quaderi NA, Schweiger S, Gaundenz K et al. (1997) Opitz G/BBB syndrome, a defect of midline development, is due to mutations in a new RING finger gene on Xp22. Nature Genetics 17: 285–291.

Rao E, Weiss B, Fukami M et al. (1997) Pseudoautosomal deletions encompassing a novel homeobox gene cause growth failure in idiopathic short stature and Turner syndrome. Nature Genetics 16: 54–63.

Rappold GA (1993) The pseudoautosomal regions of the human sex chromosomes. Human Genetics 92: 315–324.

Raudsepp T and Chowdhary BP (2008) The horse pseudoautosomal region (PAR): characterization and comparison with the human, chimp, and mouse PARS. Cytogenetic and Genome Research 121: 102–109.

Ross MT, Grafham DV, Coffay AJ et al. (2005) The DNA sequence of the human X chromosome. Nature 434: 278–280.

Shears DJ, Vassal HJ, Goodman FR et al. (1998) Mutation and deletion of the pseudoautosomal gene SHOX cause Leri‐Weill dyschondrosteosis. Nature Genetics 19: 70–73.

Further Reading

Blaschke RJ and Rappold G (2006) The pseudoautosomal regions, SHOX and disease. Current Opinion in Genetics & Development 16: 233–239.

Ellis N and Goodfellow PN (1989) The mammalian pseudoautosomal region. Trends in Genetics 5: 406–410.

Ellison JW (2008) SHOX and dyschondrosteosis and Turner syndrome. In: Epstein CJ, Erickson RP and Wynshaw‐Boris A (eds) Inborn errors of development: the molecular basis of clinical disorders of morphogenesis, chap. 77, pp. 735–739. New York, NY: Oxford University Press.

Goodfellow PJ, Darling SM, Thomas NS and Goodfellow PN (1986) A pseudoautosomal gene in man. Science 234: 740–743.

Kipling D, Salido EC, Shapiro LJ and Cooke HJ (1996) High frequency de novo alterations in the long‐range genomic structure of the mouse pseudoautosomal region. Nature Genetics 13: 78–80.

Kvaloy K, Galvagni F and Brown WRA (1994) The sequence organization of the long arm pseudoautosomal region of the human sex chromosomes. Human Molecular Genetics 3: 771–778.

Li L and Hamer DH (1995) Recombination and allelic association in the Xq/Yq homology region. Human Molecular Genetics 4: 2013–2016.

Rouyer F, Simmler MC, Johnsson C et al. (1986) A gradient of sex linkage in the pseudoautosomal region of the human sex chromosomes. Nature 319: 291–295.

Salido EC, Li XM, Yen PH et al. (1996) Cloning and expression of the mouse pseudoautosomal steroid sulphatase gene (Sts). Nature Genetics 13: 83–86.

Toder R and Graves JA (1998) CSF2RA, ANT3, and STS are autosomal in marsupials: implications for the origin of the pseudoautosomal region of mammalian sex chromosomes. Mammalian Genome 9: 373–376.

Contact Editor close
Submit a note to the editor about this article by filling in the form below.

* Required Field

How to Cite close
Ellison, Jay W(Dec 2009) Pseudoautosomal Inheritance. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1002/9780470015902.a0001460.pub2]