GENETIC VARIABILITY IN REPRODUCTION RATES IN MARINE PHYTOPLANKTON POPULATIONS
1981; Oxford University Press; Volume: 35; Issue: 6 Linguagem: Inglês
10.1111/j.1558-5646.1981.tb04981.x
ISSN1558-5646
Autores Tópico(s)Marine and coastal plant biology
ResumoThe amount of genetic variability within interbreeding populations has been an important concern for population geneticists and evolutionary biologists ever since Chetverikov (1926), Fisher (1930), Wright (1931), and Haldane (1932) discussed the potential relationship between genetic variability and evolutionary change. All individual organisms are different from each other to some degree, of course. But it is often unclear and difficult to determine how much of the variability observed is caused by environmental and developmental differences and how much is the result of genetic differences. In this study, the problem of separating environmental and genetic influences upon phenotypic variability is avoided by measuring the reproduction rates of all the different genotypes in exactly the same environment. A number of other requirements must also be met, however, to confirm that the differences in fitness that are observed in the same environment are indeed genetic in origin. 1. The first requirement is that the organisms must be fully acclimated to the experimental environment. It has been found that phytoplankton take approximately five to 20 asexual generations to acclimate (Brand et al., 198 la). Thus, the same genotype must be maintained for a number of generations to achieve complete acclimation. 2. The same genotype must be maintained in a constant environment and its fitness measured for a number of generations to confirm that the genotype reproduces at a constant rate in a constant en-
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