Evaluating the maintenance of disease-associated variation at the blood group-related gene B4galnt2 in house mice

BMC Evolutionary Biology

Research Article

Miriam Linnenbrink¹  Marie Vallier²  John F. Baines²  Laura Hindersin³  Arne Traulsen³  Maria Abou Chakra⁴ 

[1] Max Planck Institute for Evolutionary Biology, Evolutionary Genomics, Plön, Germany;Max Planck Institute for Evolutionary Biology, Evolutionary Genomics, Plön, Germany;Institute for Experimental Medicine, Section of Evolutionary Medicine, Christian-Albrechts-University of Kiel, Kiel, Germany;Max Planck Institute for Evolutionary Biology, Evolutionary Theory, Plön, Germany;Max Planck Institute for Evolutionary Biology, Evolutionary Theory, Plön, Germany;Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Canada;

关键词: B4galnt2;    Blood group;    Host-pathogen interaction;    Balancing selection;    Trade-off;    Evolutionary game theory;    Wright-fisher process;   

DOI  :  10.1186/s12862-017-1035-7

 received in 2017-03-23, accepted in 2017-08-04,  发布年份 2017

来源: Springer

【 摘 要 】

BackgroundB4galnt2 is a blood group-related glycosyltransferase that displays cis-regulatory variation for its tissue-specific expression patterns in house mice. The wild type allele, found e.g. in the C57BL/6 J strain, directs intestinal expression of B4galnt2, which is the pattern observed among vertebrates, including humans. An alternative allele class found in the RIIIS/J strain and other mice instead drives expression in blood vessels, which leads to a phenotype similar to type 1 von Willebrand disease (VWD), a common human bleeding disorder. We previously showed that alternative B4galnt2 alleles are subject to long-term balancing selection in mice and that variation in B4galnt2 expression influences host-microbe interactions in the intestine. This suggests that the costs of prolonged bleeding in RIIIS/J allele-bearing mice might be outweighed by benefits associated with resistance against gastrointestinal pathogens. However, the conditions under which such trade-offs could lead to the long-term maintenance of disease-associated variation at B4galnt2 are unclear.ResultsTo explore the persistence of B4galnt2 alleles in wild populations of house mice, we combined B4galnt2 haplotype frequency data together with a mathematical model based on an evolutionary game framework with a modified Wright-Fisher process. In particular, given the potential for a heterozygote advantage as a possible explanation for balancing selection, we focused on heterozygous mice, which express B4galnt2 in both blood vessels and the gastrointestinal tract. We show that B4galnt2 displays an interesting spatial allelic distribution in Western Europe, likely due to the recent action of natural selection. Moreover, we found that the genotype frequencies observed in nature can be produced by pathogen-driven selection when both heterozygotes and RIIIS/J homozygotes are protected against infection and the fitness cost of bleeding is roughly half that of infection.ConclusionBy comparing the results of our models to the patterns of polymorphism at B4galnt2 in natural populations, we are able to recognize the long-term maintenance of the RIIIS/J allele through host-pathogen interactions as a viable hypothesis. Further, our models identify that a putative dominant-, yet unknown protective function of the RIIIS/J allele appears to be more likely than a protective loss of intestinal B4galnt2 expression in RIIIS/J homozygotes.

【 授权许可】

CC BY   
© The Author(s). 2017