@article {903,
	title = {Sexual selection halts the relaxation of protamine 2 among rodents.},
	journal = {PloS one},
	volume = {6},
	year = {2011},
	month = {2011},
	pages = {e29247},
	abstract = {Sexual selection has been proposed as the driving force promoting the rapid evolutionary changes observed in some reproductive genes including protamines. We test this hypothesis in a group of rodents which show marked differences in the intensity of sexual selection. Levels of sperm competition were not associated with the evolutionary rates of protamine 1 but, contrary to expectations, were negatively related to the evolutionary rate of cleaved- and mature-protamine 2. Since both domains were found to be under relaxation, our findings reveal an unforeseen role of sexual selection: to halt the degree of degeneration that proteins within families may experience due to functional redundancy. The degree of relaxation of protamine 2 in this group of rodents is such that in some species it has become dysfunctional and it is not expressed in mature spermatozoa. In contrast, protamine 1 is functionally conserved but shows directed positive selection on specific sites which are functionally relevant such as DNA-anchoring domains and phosphorylation sites. We conclude that in rodents protamine 2 is under relaxation and that sexual selection removes deleterious mutations among species with high levels of sperm competition to maintain the protein functional and the spermatozoa competitive.},
	issn = {1932-6203},
	doi = {10.1371/journal.pone.0029247},
	url = {http://www.plosone.org/article/info\%3Adoi\%2F10.1371\%2Fjournal.pone.0029247},
	author = {L{\"u}ke, Lena and Vicens, Alberto and Serra, Fran{\c c}ois and Luque-Larena, Juan Jose and Dopazo, Hern{\'a}n and Roldan, Eduardo R S and Gomendio, Montserrat}
}
