. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. EVOLUTION OF RESISTANCE TO METALS 139 Foundry Cove offspring control area. 0 20 40 60 mg Cd / g dry sediment 80 100 Figure 3. Numbers of" field-collected Limnodrilus hoffmeisteri from Foundry Cove and the control area, and second generation off- spring of Foundry Cove worms surviving a 28-day exposure to sedi- ments with different Cd levels. Lines connect means, vertical lines rep- resent Three replicates per group, each replicate was started with 10 individuals. Foundry Cove and their offspring that had
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. EVOLUTION OF RESISTANCE TO METALS 139 Foundry Cove offspring control area. 0 20 40 60 mg Cd / g dry sediment 80 100 Figure 3. Numbers of" field-collected Limnodrilus hoffmeisteri from Foundry Cove and the control area, and second generation off- spring of Foundry Cove worms surviving a 28-day exposure to sedi- ments with different Cd levels. Lines connect means, vertical lines rep- resent Three replicates per group, each replicate was started with 10 individuals. Foundry Cove and their offspring that had never been exposed to metal-rich sediment. Selection experiments L. hoffmeisteri from the control area was selected for resistance to a combination of Cd, Ni, and Co in water, to determine the potential for the evolution of resistance in this population. No response to the selection was evi- dent after one generation of selection but later genera- tions showed a significantly higher resistance than the control line (Fig. 4). After three generations of selection, the difference in resistance between the selected lines and the control line averaged 66% of the difference in resis- tance between field-collected Foundry Cove worms and those from the nearby control site. Heritability determinations The potential for adaptation to metals in the control population was also assessed by determining the herita- bility of metal-resistance in this population. Regressions of the average resistance of offspring on the average resis- tance of their parents resulted in heritability estimates (±) of ± (n = 28) and ± (n = 28) (the latter value for data weighted for the number of off- spring per family). Single parent-offspring regression re- sulted in an heritability estimate of ± (n = 455). The result from the selection experiment translated into a realized heritability of ± (n = 11), some- what lower than the heritability estimates given above. b
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
