The ecological genetics of growth in Drosophila 1. Body size and developmental time on different diets 1. Body size and developmental time on different diets

摘要: 1. The interrelations between environment and the phenotypic expression of genetic differences have not received attention they merit. Laboratory studies in quantitative inheritance, either by choice character or experimental conditions, shed much light on this problem. Selection for same different environments is likely to involve qualitative physiology development. Comparative study such changes will throw genetics development generally, which turn relevant how far selection response can be pushed a given direction. Since statistical variation individuals must ultimately interpreted biological terms, unnatural barriers physiological broken down clear way greater variety analysis more widely based approach interpretation individual populations. ecology animal provides point departure guide kind environmental should studied first. suggested cuts across conventional limits quantitative, population exploits concepts methods these alternative approaches common end, it convenient descriptive label. term ‘ecological genetics’ has been adopted.2. This introductory paper first series dealing with experiments orientated along lines. largely consists quantity composition diet, growth from cage Drosophila melanogaster also other strains aseptic, synthetic diets. Body size duration larval period are taken as measures growth. There well-marked ability regulate body size, extending development, provided diet too deficient. When further reduced time lengthened well.3. To test reaction created selecting large small their performance, together that cross them, compared performance unselected diets few generations mass selection. evidence gene-environment interaction quite early selection, after six striking were detected. It concluded sub-optimal widespread population.4. within-culture variance increased growing larvae progressively deficient approximately twice great low-protein usual live yeast medium. increase attributed segregation unimportant contribute little under favourable conditions.5. Comparison repeated tests two lacking fructose ribonucleic acid revealed plasticity minor nutritional characterized positive association period. relationship reverse associated crude leads negative size. probably represents an aspect homeostasis. Genetic magnitude direction accounts apparent discrepancies estimates when deviations unselected. suggests need determining may altering rate period, differentiated respects differ controlled nutrition.