Dataset Information

Neutral Forces and Balancing Selection Interplay to Shape the Major Histocompatibility Complex Spatial Patterns in the Striped Hamster in Inner Mongolia: Suggestive of Broad-Scale Local Adaptation.

ABSTRACT:

Background

The major histocompatibility complex (MHC) plays a key role in the adaptive immune response to pathogens due to its extraordinary polymorphism. However, the spatial patterns of MHC variation in the striped hamster remain unclear, particularly regarding the relative contribution of the balancing selection in shaping MHC spatial variation and diversity compared to neutral forces.

Methods

In this study, we investigated the immunogenic variation of the striped hamster in four wild populations in Inner Mongolia which experience a heterogeneous parasitic burden. Our goal was to identify local adaptation by comparing the genetic structure at the MHC with that at seven microsatellite loci, taking into account neutral processes.

Results

We observed significant variation in parasite pressure among sites, with parasite burden showing a correlation with temperature and precipitation. Molecular analysis revealed a similar co-structure between MHC and microsatellite loci. We observed lower genetic differentiation at MHC loci compared to microsatellite loci, and no correlation was found between the two.

Conclusions

Overall, these results suggest a complex interplay between neutral evolutionary forces and balancing selection in shaping the spatial patterns of MHC variation. Local adaptation was not detected on a small scale but may be applicable on a larger scale.

SUBMITTER: Liu P

PROVIDER: S-EPMC10379431 | biostudies-literature | 2023 Jul

REPOSITORIES: biostudies-literature

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Publications

Neutral Forces and Balancing Selection Interplay to Shape the Major Histocompatibility Complex Spatial Patterns in the Striped Hamster in Inner Mongolia: Suggestive of Broad-Scale Local Adaptation.

Liu Pengbo P Li Guichang G Zhao Ning N Song Xiuping X Wang Jun J Shi Xinfei X Wang Bin B Zhang Lu L Dong Li L Li Qingduo Q Liu Qiyong Q Lu Liang L

Genes 20230722 7

<h4>Background</h4>The major histocompatibility complex (MHC) plays a key role in the adaptive immune response to pathogens due to its extraordinary polymorphism. However, the spatial patterns of MHC variation in the striped hamster remain unclear, particularly regarding the relative contribution of the balancing selection in shaping MHC spatial variation and diversity compared to neutral forces.<h4>Methods</h4>In this study, we investigated the immunogenic variation of the striped hamster in fo ...[more]

PMID: 37510404

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Project description:BackgroundGenes of the major histocompatibility complex (MHC) exhibit high levels of variability, which is believed to have arisen through pathogen-mediated selection. We investigated the relationship between parasite load and genetic diversity at selectively neutral, non-coding markers (microsatellites) and adaptive genetic variation at a functionally important part of the MHC in six independent natural populations of Brandt's voles (Lasiopodomys brandtii) from two regions of the Xilingol Grassland area of Inner Mongolia.ResultsTwo-hundred and fifty-two voles were screened for gastrointestinal parasites, and were assessed for genetic variation. Parasite screening was done through non-invasive fecal egg counts, while allelic diversity was determined via single-stranded conformation polymorphism and DNA sequencing. We detected eight distinct helminth egg morphotypes. A total of 10 microsatellite loci were genotyped and 19 unique MHC class II B alleles were isolated. The rate of nonsynonymous substitutions (dN) exceeded the rate of synonymous substitutions (dS) at putative antigen binding sites of DRB. Neutral and adaptive genetic diversity differed between the six vole populations. To test the main pathogen-driven selection hypotheses for the maintenance of host MHC diversity and parasite species-specific co-evolutionary effects, multivariate approaches (generalized linear mixed models) were used to test for associations between the MHC class II DRB genotype and infections with nematodes. We found no evidence for heterozygote advantage, and overall heterozygosity was lower than expected in the MHC alleles. We identified an association between the parasite load and specific MHC alleles in the voles, and this pattern varied between geographic regions.ConclusionsThe results suggest that MHC variability in Brandt's voles is maintained by rare allele advantage and fluctuating selection, but the data failed to show any heterozygote advantage effect. Our results add to a growing body of evidence showing that the mode and relative strength of pathogen-driven selection acting on MHC diversity varies within specific wild populations. In addition, our study contributes to the understanding of what maintains MHC diversity, of host-pathogen coevolution and of how genetic diversity is maintained in voles.

Project description:Ordos is an ecological fragile area in the upstream and midstream of the Yellow River and a component of the ecological security barrier on the northern frontier of China. With population growth in recent years, the contradiction between human beings and land resources has become increasingly prominent, leading to increased food security risks. Since 2000, the local government has implemented a series of ecological projects to guide farmers and herdsmen to transform from extensive production to intensive production, which has optimized the pattern of food production and consumption. It is necessary to study the balance between food supply and demand to evaluate food self-sufficiency. Here, we used the panel data from 2000 to 2020 collected based on random sampling surveys to reveal the characteristics of food production and consumption, the changes in food self-sufficiency rate and the dependence of food consumption on local production in Ordos. The results showed that food production and consumption dominated by grains have been increasing. The residents' diets were characterized by excessive consumption of grains and meat, and insufficient consumption of vegetables, fruits, and dairy foods. On the whole, the locality has achieved self-sufficiency, because the food supply exceeded the demand during the two decades. However, the self-sufficiency of different food types varied greatly, as some foods, such as wheat, rice, pork, poultry, and eggs, have not been self-sufficient. Due to the increased and diversified food demand of residents, food consumption became less dependent on local production and more dependent on food imported from the central and eastern China, which threatened local food security. The study can provide a scientific basis for decision-makers for the structural adjustment of agricultural and animal husbandry and the structural adjustment of food consumption, to ensure food security and sustainable utilization of land resources.

Dataset Information

Neutral Forces and Balancing Selection Interplay to Shape the Major Histocompatibility Complex Spatial Patterns in the Striped Hamster in Inner Mongolia: Suggestive of Broad-Scale Local Adaptation.

Background

Methods

Results

Conclusions

Publications

Neutral Forces and Balancing Selection Interplay to Shape the Major Histocompatibility Complex Spatial Patterns in the Striped Hamster in Inner Mongolia: Suggestive of Broad-Scale Local Adaptation.

Similar Datasets

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