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Genetic impoverishment in laboratory cultures of the test organism Chironomus riparius
Author(s) -
Nowak Carsten,
Vogt Christian,
Diogo João Barateiro,
Schwenk Klaus
Publication year - 2007
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1897/06-349r.1
Subject(s) - chironomus riparius , biology , genetic diversity , microsatellite , loss of heterozygosity , genetic variation , genetic monitoring , population , locus (genetics) , genetic variability , zoology , chironomidae , genetics , allele , ecology , genotype , larva , gene , demography , sociology
Abstract Genetic diversity among laboratory and field populations of Chironomus riparius was investigated using microsatellite DNA analysis. Individuals of midge cultures reared in 10 different laboratories showed a clear reduction in the number of alleles per locus and in the level of heterozygosity compared to two natural populations sampled in southern Germany. To reconstruct the rate of genetic impoverishment under laboratory conditions, genetic diversity was monitored in a C. riparius laboratory population for 23 generations. Additionally, 11 populations originating from different laboratories were crossed, and genetic diversity was compared among pure, crossed, and natural populations. The results demonstrate that C. riparius strains used in standard toxicity tests exhibit low levels of genetic variability. In addition, our experiments show that refreshment of stocks with individuals from other laboratories is not sufficient to restore genetic variation. Potential consequences of genetic impoverishment and improvements for toxicological bioassays are discussed.