Genetic Divergence in Body Size Among Experimental Populations of Drosophila pseudoobscura Kept at Different Temperatures

Evolution ◽  
1973 ◽  
Vol 27 (2) ◽  
pp. 278 ◽  
Author(s):  
Wyatt W. Anderson
1966 ◽  
Vol 7 (2) ◽  
pp. 255-266 ◽  
Author(s):  
Wyatt W. Anderson

1. Six initially identical populations of Drosophila pseudoobscura have been maintained in population cages for 7 years. Two populations have been kept at 16°C, two at 25°C, and two at 27°C.2. One and a half years after the start, there was no significant genetic divergence in body size among the populations. When the populations were about 6 years old, a striking genetic divergence in body size was found. The genetic difference between the populations having the smallest and the largest mean sizes is over half the total phenotypic change in size between the two extreme temperatures at which the populations were kept. The populations kept at the lower temperature have genetically larger flies than the populations kept at the higher temperatures.3. Accompanying the changes in body size were changes in the time of develop ment from egg to adult, the faster developers being the larger flies.4. The F1 hybrids from crossses between Vetukhiv's populations showed non-additivity of the genes for body size, the F1's in most cases being significantly larger than the midparent. There was no change in variability of body size in the F1 or F2 hybrids.5. The temperature-directed selection for body size found in Vetukhiv's experimental populations may well be similar in kind to that which has produced temperature-oriented geographic gradients for body size in natural populations of several species of Drosophila.


1967 ◽  
Vol 10 (3) ◽  
pp. 303-312 ◽  
Author(s):  
Osamu Kitagawa

Six experimental populations of D. pseudoobscura were maintained at three different temperatures for more than 8 years. All the populations have originally descended from the same founders. The populations were examined for evidences of genetic divergence. The pre-adult viabilities of the flies from these populations, and of their F1 and F2 hybrids, were studied at 16°C., 25°C., and 27°C. The results indicate that the populations have diverged genetically from each other. Some divergence is observed not only between populations kept at different temperatures, but also between the replicate populations kept at the same temperature.


1964 ◽  
Vol 5 (1) ◽  
pp. 150-157 ◽  
Author(s):  
Lee Ehrman

Weak but statistically significant sexual isolation has been demonstrated among Vetukhiv's six experimental populations of Drosophila pseudoobscura, all originally descended from founders taken from cultures of the same hybrids from four geographic localities. These six populations were maintained separately for almost 4½ years and then tested for the existence of sexual isolation. The sexual isolation has arisen in the absence of any selection for isolation, evidently as a by-product of genetic divergence.


1965 ◽  
Vol 6 (1) ◽  
pp. 139-146 ◽  
Author(s):  
Abd El-Khalek Mourad

Six experimental populations of Drosophila pseudoobscura were maintained in three different environments for almost four and a half years. All the populations have originally descended from the same founders. The populations were examined for evidences of genetic divergence. The longevity of the flies from four of these populations, and their F1 and F2 hybrids, was studied at 16°C. and at 27°C. The results indicate that the gene pools of some of the populations have diverged from each other.


2006 ◽  
Vol 58 (4) ◽  
pp. 562-566 ◽  
Author(s):  
C. Reigada ◽  
W.A.C. Godoy

The effect of larval density on the survival, fecundity and body size at two temperatures in experimental populations of C. megacephala was studied. No effect from simultaneous influence of density and temperature on life history characteristics of C. megacephala was found. Significant effects of density and temperature on survival, fecundity and body size were observed. The importance of these results for the population dynamics of C. megacephala is discussed.


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