MATERNAL TRANSFER OF COPPER RESISTANCE IN FATHEAD MINNOWS

• Main Authors: Elizabeth B. Peake, Laura L. Tierney, Jessica C. Locke, Alan S. Kolok
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Minnows; The Minnows
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.506.7653; http://www-heb.pac.dfo-mpo.gc.ca/congress/2002/Toxicol/peake.pdf

The overall objective of this research was to determine if differential resistance to copper (Cu) could be transmitted from adult fish to larval offspring. Differential resistance can be transferred from adults to offspring in two different ways. The first is genetic inheritance. This is supported in the literature by several studies that found that differences in Cu resistance were significantly correlated with differences in allozyme genotypes (e.g. Schlueter et al., 1995). The second way is by maternal transfer of non-genetic material (e.g. Lin et al., 2000). We conducted two experiments with fathead minnows (Pimephales promelas) to investigate these two potential methods for transfer of Cu resistance from parents to larval offspring. In our first experiment, we tested the hypothesis that genetic differences in adults were a major influence in determining the resistance of larvae. We used the same methods as detailed in Kolok (1998) to classify 48 male and 48 female adult minnows as being either Cu-susceptible or Cu-resistant. Critical swimming speeds (Ucrits) were measured for the 96 minnows before and after an 8-9 d exposure to 150 µg/L Cu. Cu resistance or susceptibility was based on the percent decrease in Ucrit after Cu exposure. After the minnows were classified, the 12 most Cu-susceptible pairs and 10 most Cu-resistant pairs were bred together. A 7-d survival test (U.S. EPA, 1994) was conducted on the larvae produced by Cu-resistant, Cu-susceptible, and naïve (previously unexposed) parents. Eighteen 600-ml beakers, each with 250 ml of Cu solution, served as test chambers. Larvae <24 h old from five to seven breeding pairs were distributed 87 evenly among the test chambers, with about 15 larvae per test chamber. There