Genetic Divergence in M. Vetukhiv's Experimental Populations of Drosophila pseudoobscura 5. A Further Study of Rudiments of Sexual Isolation

1969 ◽  
Vol 82 (1) ◽  
pp. 272 ◽  
Author(s):  
Lee Ehrman
Keyword(s):  
Genetic Divergence ◽  
Sexual Isolation ◽  
Drosophila Pseudoobscura ◽  
Experimental Populations

scholarly journals Genetic divergence in M. Vetukhiv's experimental populations of Drosophila pseudoobscura 1. Rudiments of sexual isolation

1964 ◽  
Vol 5 (1) ◽  
pp. 150-157 ◽  
Author(s):  
Lee Ehrman
Keyword(s):  
Genetic Divergence ◽  
Sexual Isolation ◽  
Drosophila Pseudoobscura ◽  
Selection For ◽  
Experimental Populations

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.

scholarly journals Genetic divergence in M. Vetukhiv's experimental populations of Drosophila pseudoobscura 3. Divergence in Body Size

1966 ◽  
Vol 7 (2) ◽  
pp. 255-266 ◽  
Author(s):  
Wyatt W. Anderson
Keyword(s):  
Body Size ◽  
Genetic Divergence ◽  
Genetic Difference ◽  
Natural Populations ◽  
Phenotypic Change ◽  
Drosophila Pseudoobscura ◽  
Experimental Populations ◽  
Lower Temperature ◽  
Two Populations ◽  
Significant Genetic Divergence

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.

scholarly journals Genetic divergence in M. Vetukhiv's experimental populations of Drosophila pseudoobscura 2. Longevity

1965 ◽  
Vol 6 (1) ◽  
pp. 139-146 ◽  
Author(s):  
Abd El-Khalek Mourad
Keyword(s):  
Genetic Divergence ◽  
Drosophila Pseudoobscura ◽  
Gene Pools ◽  
Experimental Populations

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.

scholarly journals Genetic divergence in M. Vetukhiv's experimental populations of Drosophila pseudoobscura: IV. Relative viability

1967 ◽  
Vol 10 (3) ◽  
pp. 303-312 ◽  
Author(s):  
Osamu Kitagawa
Keyword(s):  
Genetic Divergence ◽  
Drosophila Pseudoobscura ◽  
Different Temperatures ◽  
Relative Viability ◽  
Experimental Populations

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.

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