Functional evidence for differences in sperm competition in humans and chimpanzees

Bibliographic Collection: 
CARTA-Inspired Publication, APE
Publication Type: Journal Article
Authors: Anderson, M. J.; Chapman, S. J.; Videan, E. N.; Evans, E.; Fritz, J.; Stoinski, T. S.; Dixson, A. F.; Gagneux, P.
Year of Publication: 2007
Journal: Am J Phys Anthropol
Volume: 134
Edition: 2007/07/17
Number: 2
Pagination: 274-80
Date Published: Oct
Type of Article: Comparative StudyResearch Support, N.I.H., ExtramuralResearch Support, Non-U.S. Gov't
Publication Language: eng
ISBN Number: 0002-9483 (Print)0002-94
Accession Number: 17632799
Keywords: Animal, Animals, Flow Cytometry, Gorilla gorilla/physiology, Humans, Male, Mating Preference, Membrane Potential, Mitochondrial/physiology, Pan paniscus/physiology, Pan troglodytes/*physiology, Sperm Capacitation, Sperm Motility, Spermatozoa/cytology/meta

Sperm competition occurs when the gametes of or more males compete for opportunities to fertilize a given set of ova. Previous studies have demonstrated that certain morphological characteristics are affected by sperm competition intensity (e.g. relative testes size and sperm midpiece volume). This study examined whether aspects of sperm energetics may also be affected by sexual selection. We compared the membrane potential of mitochondria in live sperm between H. sapiens (single partner mating system) and P. troglodytes (multiple partner mating system). Flow cytometry of sperm stained with the carbocyanine fluorescent dye JC-1 (an assay for mitochondrial membrane potential) revealed marked differences in red fluorescence intensity. P. troglodytes sperm showed significantly higher mitochondrial membrane potential. Mitochondria provide a substantial part of the energy required for sperm motility. A higher mitochondrial loading may therefore be associated with enhanced sperm motility and/or longevity. Additionally, examination of JC-1 red fluorescence levels before and after in vitro capacitation revealed further differences. Whereas chimpanzee sperm showed maintenance of membrane potential after capacitation (in some cases even an increase), sperm from humans consistently showed reduction in membrane potential. These results indicate that the sperm of human beings and chimpanzees exhibit marked differences in mitochondrial function, which are affected by selection pressures relating to sperm competition and that these pressures differ significantly between humans and chimpanzees.


Am J Phys Anthropol. 2007 Oct;134(2):274-80.

Alternate Journal: American journal of physical anthropology
Author Address:

Conservation and Research for Endangered Species (CRES), Zoological Society of San Diego, Escondido, CA 92027, USA.

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