Table of Contents
To view the fulltext, log-in or choose pay-per-view options:
Get Access

Sex and death in birds: A model of dosage compensation that predicts lethality of sex chromosome aneuploids

Graves J.A.M.
Research School of Biological Sciences, The Australian National University, Canberra (Australia) Cytogenet Genome Res 101:278–282 (2003) (DOI:10.1159/000074349)


Birds show female heterogamety, with ZZ males and ZW females. It is still not clear whether the W is female-determining, or whether two doses of the Z chromosomes are male-determining, or both. This question could easily be settled by the sexual phenotypes of ZZW and ZO birds, in the same way that the sexual phenotypes of XXY and XO showed that the Y is male determining in humans, but that the dosage of an X-borne gene determines sex in Drosophila. However, despite extensive searches, no ZZW or ZO diploid birds have been satisfactorily documented, so we must assume that these genotypes are embryonic lethals. Given that ZW and ZZ are viable and the W contains few genes it is not clear why this should be so. Here I propose that sex chromosome aneuploids are lethal in chicken because, to achieve dosage compensation, a locus on the W chromosome controls the upregulation of genes on the Z in ZW females. ZO birds would therefore have only half the normal dose of Z-linked gene product and ZZW would have twice the amount, both of which would undoubtedly be incompatible with life. Reports of other aneuploids and triploids are also consistent with this hypothesis.   


Individual Users: Register with Karger Login Information

Please create your User ID & Password

Contact Information

I have read the Karger Terms and Conditions and agree.

Pay-per-View Options
Direct payment This item at the regular price: USD 38.00
Payment from account With a Karger Pay-per-View account (down payment USD 150) you profit from a special rate for this and other single items.
This item at the discounted price: USD 26.50