Breeding system and demography shape population genetic structure across ecological and climatic zones in the African freshwater snail, Bulinus forskalii (Gastropoda, Pulmonata), intermediate host for schistosomes

Jennifer Gow, Leslie Robert Noble, D. Rollinson, R. Mimpfoundi, Catherine Sue Jones

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

The role of breeding system and population bottlenecks in shaping the distribution of neutral genetic variation among populations inhabiting patchily distributed, ephemeral water bodies was examined for the hermaphroditic freshwater snail Bulinus forskalii, intermediate host for the medically important trematode Schistosoma guineensis. Levels of genetic variation at 11 microsatellite loci were assessed for 600 individuals sampled from 19 populations that span three ecological and climatic zones (ecozones) in Cameroon, West Africa. Significant heterozygote deficiencies and linkage disequilibria indicated very high selfing rates in these populations. Despite this and the large genetic differentiation detected between populations, high levels of genetic variation were harboured within these populations. The high level of gene flow inferred from assignment tests may be responsible for this pattern. Indeed, metapopulation dynamics, including high levels of gene flow as well as extinction/contraction and recolonization events, are invoked to account for the observed population structuring, which was not a consequence of isolation-by-distance. Because B. forskalii populations inhabiting the northern, Sahelian area are subject to more pronounced annual cycles of drought and flood than the southern equatorial ones, they were expected to be subject to population bottlenecks of increased frequency and severity and, therefore, show reduced genetic variability and elevated population differentiation. Contrary to predictions, the populations inhabiting the most northerly ecozone exhibited higher genetic diversity and lower genetic differentiation than those in the most southerly one, suggesting that elevated gene flow in this region is counteracting genetic drift.

Original languageEnglish
Pages (from-to)3561-3573
Number of pages12
JournalMolecular Ecology
Volume13
Issue number11
DOIs
Publication statusPublished - Nov 2004

Keywords

  • Bulinus forskalii
  • gene flow
  • metapopulation
  • microsatellites
  • null allele
  • self-fertilization
  • MATING SYSTEM
  • MICROSATELLITE LOCI
  • BIOMPHALARIA-GLABRATA
  • MULTILOCUS GENOTYPES
  • SELFING POPULATIONS
  • PLANORBIDAE
  • DISPERSAL
  • DIVERSITY
  • EVOLUTION
  • GLOBOSUS

Cite this

@article{812dcaee6aba4220a61c63cfead101fb,
title = "Breeding system and demography shape population genetic structure across ecological and climatic zones in the African freshwater snail, Bulinus forskalii (Gastropoda, Pulmonata), intermediate host for schistosomes",
abstract = "The role of breeding system and population bottlenecks in shaping the distribution of neutral genetic variation among populations inhabiting patchily distributed, ephemeral water bodies was examined for the hermaphroditic freshwater snail Bulinus forskalii, intermediate host for the medically important trematode Schistosoma guineensis. Levels of genetic variation at 11 microsatellite loci were assessed for 600 individuals sampled from 19 populations that span three ecological and climatic zones (ecozones) in Cameroon, West Africa. Significant heterozygote deficiencies and linkage disequilibria indicated very high selfing rates in these populations. Despite this and the large genetic differentiation detected between populations, high levels of genetic variation were harboured within these populations. The high level of gene flow inferred from assignment tests may be responsible for this pattern. Indeed, metapopulation dynamics, including high levels of gene flow as well as extinction/contraction and recolonization events, are invoked to account for the observed population structuring, which was not a consequence of isolation-by-distance. Because B. forskalii populations inhabiting the northern, Sahelian area are subject to more pronounced annual cycles of drought and flood than the southern equatorial ones, they were expected to be subject to population bottlenecks of increased frequency and severity and, therefore, show reduced genetic variability and elevated population differentiation. Contrary to predictions, the populations inhabiting the most northerly ecozone exhibited higher genetic diversity and lower genetic differentiation than those in the most southerly one, suggesting that elevated gene flow in this region is counteracting genetic drift.",
keywords = "Bulinus forskalii, gene flow, metapopulation, microsatellites, null allele, self-fertilization, MATING SYSTEM, MICROSATELLITE LOCI, BIOMPHALARIA-GLABRATA, MULTILOCUS GENOTYPES, SELFING POPULATIONS, PLANORBIDAE, DISPERSAL, DIVERSITY, EVOLUTION, GLOBOSUS",
author = "Jennifer Gow and Noble, {Leslie Robert} and D. Rollinson and R. Mimpfoundi and Jones, {Catherine Sue}",
year = "2004",
month = "11",
doi = "10.1111/J.1365-294X.2004.02339.X",
language = "English",
volume = "13",
pages = "3561--3573",
journal = "Molecular Ecology",
issn = "0962-1083",
publisher = "Wiley-Blackwell",
number = "11",

}

TY - JOUR

T1 - Breeding system and demography shape population genetic structure across ecological and climatic zones in the African freshwater snail, Bulinus forskalii (Gastropoda, Pulmonata), intermediate host for schistosomes

AU - Gow, Jennifer

AU - Noble, Leslie Robert

AU - Rollinson, D.

AU - Mimpfoundi, R.

AU - Jones, Catherine Sue

PY - 2004/11

Y1 - 2004/11

N2 - The role of breeding system and population bottlenecks in shaping the distribution of neutral genetic variation among populations inhabiting patchily distributed, ephemeral water bodies was examined for the hermaphroditic freshwater snail Bulinus forskalii, intermediate host for the medically important trematode Schistosoma guineensis. Levels of genetic variation at 11 microsatellite loci were assessed for 600 individuals sampled from 19 populations that span three ecological and climatic zones (ecozones) in Cameroon, West Africa. Significant heterozygote deficiencies and linkage disequilibria indicated very high selfing rates in these populations. Despite this and the large genetic differentiation detected between populations, high levels of genetic variation were harboured within these populations. The high level of gene flow inferred from assignment tests may be responsible for this pattern. Indeed, metapopulation dynamics, including high levels of gene flow as well as extinction/contraction and recolonization events, are invoked to account for the observed population structuring, which was not a consequence of isolation-by-distance. Because B. forskalii populations inhabiting the northern, Sahelian area are subject to more pronounced annual cycles of drought and flood than the southern equatorial ones, they were expected to be subject to population bottlenecks of increased frequency and severity and, therefore, show reduced genetic variability and elevated population differentiation. Contrary to predictions, the populations inhabiting the most northerly ecozone exhibited higher genetic diversity and lower genetic differentiation than those in the most southerly one, suggesting that elevated gene flow in this region is counteracting genetic drift.

AB - The role of breeding system and population bottlenecks in shaping the distribution of neutral genetic variation among populations inhabiting patchily distributed, ephemeral water bodies was examined for the hermaphroditic freshwater snail Bulinus forskalii, intermediate host for the medically important trematode Schistosoma guineensis. Levels of genetic variation at 11 microsatellite loci were assessed for 600 individuals sampled from 19 populations that span three ecological and climatic zones (ecozones) in Cameroon, West Africa. Significant heterozygote deficiencies and linkage disequilibria indicated very high selfing rates in these populations. Despite this and the large genetic differentiation detected between populations, high levels of genetic variation were harboured within these populations. The high level of gene flow inferred from assignment tests may be responsible for this pattern. Indeed, metapopulation dynamics, including high levels of gene flow as well as extinction/contraction and recolonization events, are invoked to account for the observed population structuring, which was not a consequence of isolation-by-distance. Because B. forskalii populations inhabiting the northern, Sahelian area are subject to more pronounced annual cycles of drought and flood than the southern equatorial ones, they were expected to be subject to population bottlenecks of increased frequency and severity and, therefore, show reduced genetic variability and elevated population differentiation. Contrary to predictions, the populations inhabiting the most northerly ecozone exhibited higher genetic diversity and lower genetic differentiation than those in the most southerly one, suggesting that elevated gene flow in this region is counteracting genetic drift.

KW - Bulinus forskalii

KW - gene flow

KW - metapopulation

KW - microsatellites

KW - null allele

KW - self-fertilization

KW - MATING SYSTEM

KW - MICROSATELLITE LOCI

KW - BIOMPHALARIA-GLABRATA

KW - MULTILOCUS GENOTYPES

KW - SELFING POPULATIONS

KW - PLANORBIDAE

KW - DISPERSAL

KW - DIVERSITY

KW - EVOLUTION

KW - GLOBOSUS

U2 - 10.1111/J.1365-294X.2004.02339.X

DO - 10.1111/J.1365-294X.2004.02339.X

M3 - Article

VL - 13

SP - 3561

EP - 3573

JO - Molecular Ecology

JF - Molecular Ecology

SN - 0962-1083

IS - 11

ER -