Frequent Multiple Insemination in a Natural Population of Drosophila pseudoobscura

1974 ◽  
Vol 108 (963) ◽  
pp. 709-711 ◽  
Author(s):  
Wyatt W. Anderson
Keyword(s):  
Natural Population ◽  
Drosophila Pseudoobscura

Population Genetics of Mexican Drosophila. V. A High Rate of Multiple Insemination in a Natural Population of Drosophila pseudoobscura

1980 ◽  
Vol 116 (4) ◽  
pp. 493-503 ◽  
Author(s):  
L. Levine ◽  
M. Asmussen ◽  
O. Olvera ◽  
J. R. Powell ◽  
M. E. de la Rosa ◽  
...  
Keyword(s):  
Population Genetics ◽  
Natural Population ◽  
High Rate ◽  
Drosophila Pseudoobscura

scholarly journals POLYMORPHISM FOR DIMERIZING ABILITY AT THE ESTERASE-5 LOCUS IN DROSOPHILA PSEUDOOBSCURA

Genetics ◽  
1976 ◽  
Vol 82 (1) ◽  
pp. 53-62
Author(s):  
Gary Cobbs
Keyword(s):  
Molecular Mechanism ◽  
Natural Population ◽  
Drosophila Pseudoobscura ◽  
The Third ◽  
New Alleles

ABSTRACT Three new alleles are reported at the esterase-5 locus of Drosophila pseudoobscura. All three of these alleles are different from those previously reported in their ability to dimerize. One allele will not form heterodimers or homodimers and exists only as a monomer. A second allele does form heterodimers but will not form homodimers. The third allele forms both hetero- and homodimers as well as forming monomers. Estimates of the frequency of these alleles in a natural population are given. The existence of these is discussed with respect to recently proposed models for a molecular mechanism for heterosis.

scholarly journals DRIFT OR SELECTION: A STATISTICAL TEST OF GENE FREQUENCY VARIATION OVER GENERATIONS

Genetics ◽  
1977 ◽  
Vol 87 (2) ◽  
pp. 371-379
Author(s):  
Henry E Schaffer ◽  
Darrell Yardley ◽  
Wyatt W Anderson
Keyword(s):  
Zea Mays ◽  
Allele Frequency ◽  
Natural Population ◽  
Gene Frequency ◽  
Statistical Tests ◽  
Statistical Test ◽  
Directional Selection ◽  
Drosophila Pseudoobscura ◽  
Frequency Variation ◽  
Experimental Procedure

ABSTRACT The method used by Fisher and Ford (1947) to study the spread of a gene in a natural population has been modified to analyze the variation in allele frequencies from generation to generation in a common experimental procedure. A further analysis has been developed that is more sensitive to directional trends in the allele frequency over generations, and its use in detecting the action of directional selection on gene frequency at a locus is discussed. The power of each of these statistical tests is calculated for a number of cases, and the tests are applied to sets of isozyme data from Drosophila pseudoobscura and Zea mays.

scholarly journals DENSITY- AND FREQUENCY-DEPENDENT SELECTION AT THE Mdh-2 LOCUS IN DROSOPHILA PSEUDOOBSCURA

Genetics ◽  
1981 ◽  
Vol 97 (3-4) ◽  
pp. 679-701
Author(s):  
Mirjana ToŠić ◽  
Francisco J Ayala
Keyword(s):  
Natural Population ◽  
Genetic Background ◽  
Inverse Relationship ◽  
High Density ◽  
Drosophila Pseudoobscura ◽  
Frequency Dependent ◽  
Frequency Dependent Selection ◽  
Dehydrogenase Enzyme ◽  
Intergenotypic Competition ◽  
Better Than

ABSTRACT We have studied differenccs in the number of Drosophila pseudoobscura produced in a culture when the flies differ with respect to two alleles (F and S) at the Mdh-2 locus, which codes for a malate dehydrogenase enzyme. The studies were done at low and at high density in two- and three-genotype combinations (S/S, F/F and S/F), with one-genotype cultures as controls.—— Density affects the fitness of the Mdh-2 genotypes. Different genotypes are differently affected, and the genotype of the competitors also makes a difference on the fitness of a given genotype. When three genotypes are present in a culture, particularly at high density, intergenotypic competition is less intense than intragenotypic competition at several frequency combinations. That is, there is "overcompensation": the three genotypes together exploit the environmental resources better than one genotype alone.———The fitness of the genotypes is frequency dependent in both two-genotype and three-genotype combinations. An inverse relationship between frequency and fitness is observed at high density. This may lead to a stable polymorphism, because the fitness of a genotype increases as its frequency decreases.——Forty independent strains, sampled from a natural population, were used in the experiments. This ensures that more than 95% of the variation present in the genome in the natural population is also present is the experimental cultures. It also ensures that the genetic background of the Mdh-2 alleles is randomized in the same way as it is in nature. However, the possibility remains that Mdh-2 alleles in nature are nonrandomly associated with alleles at closely linked loci. If linkage disequilibrium is present in the experiments because it exists in nature, then the observed effects (such as frequency-dependent selection) would affect the Mdh-2 locus in nature as well.

Reproduction of the Roman snail (Helix pomatia L.) from a local natural population in farm conditions and in a natural habitat

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Maciej Ligaszewski ◽  
Przemysław Pol
Keyword(s):  
Natural Population ◽  
Natural Habitat ◽  
Local Population ◽  
Helix Pomatia ◽  
Second Phase ◽  
Animal Reproduction ◽  
Snail Helix Pomatia ◽  
June July ◽  
A Site

AbstractThe aim of this study was to compare the quality of clutches and reproduction results of two groups of Roman snails (Helix pomatia) from the same local population, laying eggs simultaneously in semi-natural farm conditions and in a natural habitat. The study material were Roman snails aged 2 or more years which had entered the third phenological season of their life and thus the first season of sexual maturity. Observations were conducted at an earthen enclosure in a greenhouse belonging to the experimental farm for edible snails at the National Research Institute of Animal Reproduction in Balice near Kraków (Poland) as well as at a site where a local population naturally occurs in the uncultivated park surrounding the Radziwiłł Palace. In the June-July season, differences among such parameters as weight of clutch, number of eggs in clutch, mean egg weight, and hatchling percentage when compared to the total number of eggs in the clutch were compared. It was determined that clutches of eggs from the natural population laid in the greenhouse were of lesser weight (P<0.01), contained fewer eggs (P<0.05), and the mean weight of individual eggs was less (P<0.05) than in clutches laid simultaneously in a natural habitat. Both in the greenhouse and the natural habitat, in the first phase of laying eggs (June) the weight of the clutch and number of eggs its contained were greater than in the second phase (July). However, only for snails laying eggs in the greenhouse were these differences statistically significant (P<0.05) and highly significant (P<0.01), respectively. Statistically significant differences were not observed in hatchling percentage between eggs laid in the greenhouse and the natural habitat. The lower number of eggs laid in the farmed conditions of the greenhouse was successfully compensated for by the absence of mass destruction by rodents which occurred in the natural habitat.

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