Sexual selection by female immunity against paternal antigens can fix loss of function alleles

Bibliographic Collection: 
CARTA-Inspired Publication, APE
Publication Type: Journal Article
Authors: Ghaderi, D.; Springer, S. A.; Ma, F.; Cohen, M.; Secrest, P.; Taylor, R. E.; Ajit Varki; Gagneux, P.
Year of Publication: 2011
Journal: Proc Natl Acad Sci U S A
Volume: 108
Edition: 2011/10/12
Number: 43
Pagination: 17743-8
Date Published: Oct 25
Type of Article: Research Support, N.I.H., ExtramuralResearch Support, Non-U.S. Gov't
Publication Language: eng
ISBN Number: 1091-6490 (Electronic)00
Keywords: Animal/*physiology, Animals, Antibodies/*immunology, Antigens/immunology, Female, Gene Frequency, Genetics, Humans, Knockout, Male, Mating Preference, Mice, Mixed Function Oxygenases/*genetics/metabolism, Neuraminic Acids/*immunology, Pa, Population

Humans lack the common mammalian cell surface molecule N-glycolylneuraminic acid (Neu5Gc) due to a CMAH gene inactivation, which occurred approximately three million years ago. Modern humans produce antibodies specific for Neu5Gc. We hypothesized that anti-Neu5Gc antibodies could enter the female reproductive tract and target Neu5Gc-positive sperm or fetal tissues, reducing reproductive compatibility. Indeed, female mice with a human-like Cmah(-/-) mutation and immunized to express anti-Neu5Gc antibodies show lower fertility with Neu5Gc-positive males, due to prezygotic incompatibilities. Human anti-Neu5Gc antibodies are also capable of targeting paternally derived antigens and mediate cytotoxicity against Neu5Gc-bearing chimpanzee sperm in vitro. Models of populations polymorphic for such antigens show that reproductive incompatibility by female immunity can drive loss-of-function alleles to fixation from moderate initial frequencies. Initially, the loss of a cell-surface antigen can occur due to drift in isolated populations or when natural selection favors the loss of a receptor exploited by pathogens, subsequently the same loss-of-function allele can come under sexual selection because it avoids being targeted by the female immune system. Thus, we provide evidence of a link between sexual selection and immune function: Antigenicity in females can select against foreign paternal antigens on sperm and rapidly fix loss-of-function alleles. Similar circumstances existed when the CMAH null allele was polymorphic in ancestral hominins, just before the divergence of Homo from australopithecines.


Proc Natl Acad Sci U S A. 2011 Oct 25;108(43):17743-8. doi: 10.1073/pnas.1102302108. Epub 2011 Oct 10. 

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Alternate Journal: Proceedings of the National Academy of Sciences of the United States of America
Author Address:

Center for Academic Research and Training in Anthropogeny, Glycobiology Research and Training Center and Departments of Medicine and Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA 92093, USA.