Genetic differentiation in geographically close populations of the water rat Nectomys squamipes (Rodentia, Sigmodontinae) from the Brazilian Atlantic Forest

Genetics and Molecular Biology

L.s. Maroja¹  F.c. Almeida¹  H.n. Seuánez¹ 

[1] ,Universidade Federal do Rio de Janeiro Departamento de Genética Rio de Janeiro RJ ,Brazil

关键词: microsatellites;    migration;    population genetics;    Schistosoma mansoni host;    Sigmodontinae;   

DOI  :  10.1590/S1415-47572003000400002

来源: SciELO

【 摘 要 】

We examined the genetic structure and the effects of a bottleneck in populations of the water rat Nectomys squamipes, a primary host of Schistosoma mansoni. Eight microsatellite loci were studied in 7 populations from the Sumidouro region of the Brazilian state of Rio de Janeiro. Our data, covering a four-year period during which a bottleneck occurred, revealed substantial variation (6-31 alleles per locus) and high levels of both observed (0.718-0.789) and expected (0.748-0.832) heterozygosity. Most populations were in Hardy-Weinberg equilibrium without linkage disequilibrium between loci. Overall average genetic differentiation between populations (estimated with the F ST (q) and R ST (r) analogues was 0.037 for q and 0.060 for r. There was significant allelic and genotypic differentiation between populations, especially in pairwise comparisons that included the most geographically isolated population. Direct migration estimates showed a low rate of migration, indicating that infected N. squamipes populations had a limited ability to spread S. mansoni. When the pre- and post-bottleneck populations were compared there was no detectable reduction in heterozygosity or allele number, although a significant excess of heterozygosity was detected in the post-bottleneck population.

【 授权许可】

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