The eutherian pseudoautosomal region

Terje Raudsepp, Bhanu P. Chowdhary

Research output: Contribution to journalReview articlepeer-review

73 Citations (Scopus)


The pseudoautosomal region (PAR) is a unique segment of sequence homology between differentiated sex chromosomes where recombination occurs during meiosis. Molecular and functional properties of the PAR are distinctive from the autosomes and the remaining regions of the sex chromosomes. These include a higher rate of recombination than genome average, bias towards GC-substitutions and increased interindividual nucleotide divergence and mutations. As yet, the PAR has been physically demarcated in only 28 eutherian species representing 6 mammalian orders. Murid rodents have the smallest, gene-poorest and most diverged PARs. Other eutherian PARs are largely homologous but differ in size and gene content, being the smallest in equids and human/simian primates and much larger in other eutherians. Because pseudoautosomal genes escape X inactivation, their dosage changes with sex chromosome aneuploidies, whereas phenotypic effects of the latter depend on the size and gene content of the PAR. Thus, X monosomy is more viable in mice, humans and horses than in species with larger PARs. Presently, little is known about the functions of PAR genes in individual species, though human studies suggest their involvement in early embryonic development. The PAR is, thus, of evolutionary, genetic and biomedical significance and a 'research hotspot' in eutherian genomes.

Original languageEnglish
Pages (from-to)81-94
Number of pages14
JournalCytogenetic and Genome Research
Issue number2-3
Publication statusPublished - Mar 1 2016
Externally publishedYes


  • Comparative organization
  • Eutherian mammals
  • Haploinsufficiency
  • Pseudoautosomal genes
  • Pseudoautosomal region
  • Recombination
  • Sex chromosomes
  • X aneuploidy

ASJC Scopus subject areas

  • Molecular Biology
  • Genetics
  • Genetics(clinical)


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