Published Online: 15 DEC 2009
Copyright © 2001 John Wiley & Sons, Ltd. All rights reserved.
How to Cite
Ellison, J. W. 2009. Pseudoautosomal Inheritance. eLS. .
- Published Online: 15 DEC 2009
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.
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.
- sex chromosomes;