How Ebola Impacts Genetics of Western Lowland Gorilla Populations

Pascaline J Le Gouar,Eric J Petit,Dominique Vallet,Florence Levréro,Magdalena Bermejo,Sylvain Gatti,Laetitia David,Nelly Ménard

doi:10.1371/journal.pone.0008375

Abstract

BackgroundEmerging infectious diseases in wildlife are major threats for both human health and biodiversity conservation. Infectious diseases can have serious consequences for the genetic diversity of populations, which could enhance the species' extinction probability. The Ebola epizootic in western and central Africa induced more than 90% mortality in Western lowland gorilla population. Although mortality rates are very high, the impacts of Ebola on genetic diversity of Western lowland gorilla have never been assessed.Methodology/Principal FindingsWe carried out long term studies of three populations of Western lowland gorilla in the Republic of the Congo (Odzala-Kokoua National Park, Lossi gorilla sanctuary both affected by Ebola and Lossi's periphery not affected). Using 17 microsatellite loci, we compared genetic diversity and structure of the populations and estimate their effective size before and after Ebola outbreaks. Despite the effective size decline in both populations, we did not detect loss in genetic diversity after the epizootic. We revealed temporal changes in allele frequencies in the smallest population.Conclusions/SignificanceImmigration and short time elapsed since outbreaks could explain the conservation of genetic diversity after the demographic crash. Temporal changes in allele frequencies could not be explained by genetic drift or random sampling. Immigration from genetically differentiated populations and a non random mortality induced by Ebola, i.e., selective pressure and cost of sociality, are alternative hypotheses. Understanding the influence of Ebola on gorilla genetic dynamics is of paramount importance for human health, primate evolution and conservation biology.

Highlights

Emerging infectious diseases in wildlife, raising from complex relationships between social and environmental factors, are accepted as a major threat for both human health and biodiversity conservation [1,2,3,4,5,6,7]
The Ebola virus received a lot of attention from human health and conservation biology scientists because of his rapid spread through central Africa and the high mortality rate it induced in humans and nonhuman primates [13,14,15,16,17,18,19,20,21,22,23,24]
Absence of Genetic Diversity Loss Despite the high mortality induced by Ebola and the significant decline of the effective size estimates, no loss of rare allele was detected after the epizootic

Summary

Introduction

Emerging infectious diseases in wildlife, raising from complex relationships between social and environmental factors, are accepted as a major threat for both human health and biodiversity conservation [1,2,3,4,5,6,7]. These diseases often reduce abundance of wildlife populations to low density, increasing their extinction probability, especially in the case of frequency-dependent outbreaks [8,9,10]. Mortality rates are very high, the impacts of Ebola on genetic diversity of Western lowland gorilla have never been assessed

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