Table of Contents
International Journal of Evolutionary Biology
Volume 2012 (2012), Article ID 947381, 6 pages
http://dx.doi.org/10.1155/2012/947381
Research Article

Allelic Expression of Drosophila Protamines during Spermatogenesis

Department of Biology, The University of Western Ontario, London, ON, Canada N6A 5B7

Received 28 November 2011; Accepted 4 January 2012

Academic Editor: Jose M. Eirin-Lopez

Copyright © 2012 Rachelle L. Kanippayoor and Amanda J. Moehring. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

In typical somatic cells, DNA is tightly organized by histones that are necessary for its proper packaging into the nucleus. In sexually-reproducing animals, the haploid product of male meiosis must be further condensed to fit within sperm heads, thus requiring an even greater degree of packaging. This is accomplished in most organisms by replacing histones with protamines, which allows DNA to be compacted into the reduced space. In mammals, protamines are produced after meiosis is complete and are transcribed by the single allele present in the haploid genome that is to be packaged into the sperm head. Here, we present our findings that protamine expression occurs from both alleles in diploid cells, rather than haploid cells, in two species of Drosophila. The differential allelic expression of protamines likely influences the selective pressures that shape their evolution.