Chromosome Function: Sex Differences


The distinct development of females and males is usually the consequence of differences in their sex chromosome constitution. To compensate for these differences, the sexes adjust the expression of sex‐linked genes. Some inheritance patterns depend on the sex or sex chromosome make‐up of a parent.

Keywords: sex chromosomes (X, Y, Z, W); sex determination; dosage compensation; female/male; sex‐based inheritance patterns

Figure 1.

Summary of the sex‐determining mechanisms of humans, flies and worms as described in the text. Some details have been deleted for simplicity, including the autoregulation of Sxl expression that maintains it in the mode set by the X:A ratio, the DAX1/SRY interaction, and some of the genes in the regulatory cascades.

Figure 2.

Summary of some solutions to the ‘gene dosage problem’, as described in the text. (a) X‐inactivation control in mammals, simplified for clarity by not showing that initially both X‐chromosomes accumulate Xist RNA. The X‐chromosome drawn in green has been inactivated, except for its Xist locus and its pseudoautosomal region. (b) Summary of the situation in flies (the DCC complex is shown schematically as a clump of circles) and nematodes (the chromosome binding complex is shown schematically as a clump of diamonds). As in Figure , autoregulation of Sxl is not shown.



Amrein H (2000) Multiple RNA–protein interactions in Drosophila dosage compensation. Genome Biology 1: Reviews 1030.

Avner P and Heard E (2001) X‐chromosome inactivation: counting, choice and initiation. Nature Reviews Genetics 2: 59–67.

Charlesworth B and Charlesworth D (2000) The degeneration of Y chromosomes. Philosophical Transactions of the Royal Society of London Series B–Biological Sciences 355: 1563–1572.

Christiansen AE, Keisman EL, Ahmad SM and Baker BS (2002) Sex comes in from the cold: the integration of sex and pattern. Trends in Genetics 18: 510–516.

Goodwin EB and Ellis RE (2002) Turning clustering loops: sex determination in Caenorhabditis elegans. Current Biology 12: R111–R120.

Jacobs HT (2003) Disorders of mitochondrial protein synthesis. Human Molecular Genetics 2: R293–301.

Koopman P, Gubbay J, Vivian N, Goodfellow P and Lovell‐Badge R (1991) Male development of chromosomally female mice transgenic for Sry. Nature 351: 117–121.

Matsuda M, Nagahama Y, Shinomiya A et al. (2002) DMY is a Y‐specific DM‐domain gene required for male development in the medaka fish. Nature 417: 559–563.

Meller VH and Kuroda MI (2002) Sex and the single chromosome. Advances in Genetics 46: 1–24.

Meyer BJ (2000) Sex in the worm: counting and compensating X‐chromosome dose. Trends in Genetics 16: 247–253.

Morrish BC and Sinclair AH (2002) Vertebrate sex determination: many means to an end. Reproduction 124: 447–457.

Parisi M, Nuttall R, Naiman D et al. (2003) Paucity of genes on the Drosophila X chromosome showing male‐biased expression. Science 299: 697–700.

Raymond CS, Shamu CE, Shen MM et al. (1998) Evidence for evolutionary conservation of sex‐determining genes. Nature 391: 691–695.

Rice WR (1984) Sex‐chromosomes and the evolution of sexual dimorphism. Evolution 38: 735–742.

Schmahl J and Capel B (2003) Cell proliferation is necessary for the determination of male fate in the gonad. Developmental Biology 258: 264–276.

Schutt C and Nöthiger R (2000) Structure, function and evolution of sex‐determining systems in Dipteran insects. Development 127: 667–677.

Skaletsky H, Kuroda‐Kawaguchi T, Minx PJ et al. (2003) The male‐specific region of the human Y chromosome is a mosaic of discrete sequence classes. Nature 423: 825–837.

Stratton MR, Ford D, Neuhasen S et al. (1994) Familial male breast cancer is not linked to the BRCA1 locus on chromosome 17q. Nature Genetics 7: 103–107.

Swain A, Narvaez V, Burgoyne P, Camerino G and Lovell‐Badge R (1998) Dax1 antagonizes Sry action in mammalian sex determination. Nature 391: 761–767.

Tilghman SM (1999) The sins of the fathers and mothers: genomic imprinting in mammalian development. Cell 96: 185–193.

Further Reading

Carvalho AB (2002) Origin and evolution of the Drosophila Y chromosome. Current Opinion in Genetics & Development 12: 664–668.

Cline TW and Meyer BJ (1996) Vive la difference: males vs females in flies vs worms. Annual Review of Genetics 30: 637–702.

Grutzner F, Rens W, Tsend‐Ayush E et al. (2004) In the platypus as meiotic chain of ten sex chromosomes shares genes with the bird Z and mammal X chromosomes. Nature 432: 913–917.

Hodgkin J (2002) Exploring the envelope. Systematic alteration in the sex‐determination system of the nematode Caenorhabditis elegans. Genetics 162: 767–780.

Huynh KD and Lee JT (2001) Imprinted X inactivation in eutherians: a model of gametic execution and zygotic relaxation. Current Opinion in Cell Biology 13: 690–697.

Marin I and Baker BS (1998) The evolutionary dynamics of sex determination. Science 281: 1990–1994.

Nicholls RD, Saitoh S and Horsthemke B (1998) Imprinting in Prader–Willi and Angelman syndromes. Trends in Genetics 14: 194–200.

Panning B and Jaenisch R (1998) RNA and the epigenetic regulation of X chromosome inactivation. Cell 93: 305–308.

Pomiankowski A, Nöthiger R and Wilkins A (2004) The evolution of the Drosophilasex‐determination pathway. Genetics 166: 1761–1773.

Schafer AJ and Goodfellow PN (1996) Sex determination in humans. Bioessays 18: 955–963.

Werren JH and Beukeboom LW (1998) Sex determination, sex ratios and genetic conflict. Annual Review of Ecology and Systematics 29: 233–261.

This article was reviewed by the authors in 2013 who suggested the following eLS articles for updates to this material:

Mammalian Sex Determination

SRY, Sex Determination and Gonadal Differentiation

Sex Chromosomes

X‐chromosome Inactivation and Disease

Dosage Compensation Mechanisms: Evolution

Y‐chromosome‐linked Traits

Mammalian Sex Chromosome Evolution

Evolution and Organization of Monotreme Sex Chromosomes

Evolution of the Mammalian X Chromosome

Sex Chromosome Abnormalities

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

* Required Field

How to Cite close
Mueller, Jacob L, and Wolfner, Mariana F(Sep 2005) Chromosome Function: Sex Differences. In: eLS. John Wiley & Sons Ltd, Chichester. [doi: 10.1038/npg.els.0003939]