scholarly journals THE ALCOHOL DEHYDROGENASE POLYMORPHISM IN POPULATIONS OF DROSOPHILA MELANOGASTER. I. SELECTION IN DIFFERENT ENVIRONMENTS

Genetics ◽  
1978 ◽  
Vol 90 (1) ◽  
pp. 161-191
Author(s):  
W van Delden ◽  
A C Boerema ◽  
A Kamping
Keyword(s):  
Drosophila Melanogaster ◽  
Alcohol Dehydrogenase ◽  
Experimental Evidence ◽  
Balancing Selection ◽  
Adult Survival ◽  
High Survival ◽  
High Humidity ◽  
Allozyme Polymorphism ◽  
Degree Of Dominance ◽  
Frequency Changes

ABSTRACT The allozyme polymorphism at the alcohol dehydrogenase locus in Drosophila melanogaster was studied in order to obtain experimental evidence about the maintenance of this polymorphism. Populations started with different initial allele frequencies from homozygous F and S lines showed a convergence of frequencies on regular food at 25°, leading to values equal to those in the base populations. These results were interpreted as due to some kind of balancing selection. In populations kept at 29.8°, a lower equilibrium F frequency was attained. Addition of ethanol and some other alcohols to the food gave a rapid increase in F frequency, and high humidity decreased the F frequency slightly. Combination or alternation of ethanol and high humidity had variable effects in the populations tested. For a further analysis of the allele-frequency changes, estimates were obtained for egg-to-adult survival under different conditions and for adult survival on ethanol-supplemented food. On ethanol food (both at regular and high humidity), egg-to-adult survival of SS homozygotes was considerably lower than that of the FF and FS genotypes. Under regular conditions of food, temperature and humidity, a tendency to heterozygote superiority was observed, while at high humidity a relative high survival of SS was noticed in some tests. Adult survival of SS was lower than that of FF, but FS was generally intermediate, though the degree of dominance differed between populations. The results are consistent with the hypothesis of the occurrence of selection at the Adh locus.

scholarly journals THE GENETIC VARIABILITY OF THIRD CHROMOSOMES IN A LOCAL POPULATION OF DROSOPHILA MELANOGASTER

Genetics ◽  
1976 ◽  
Vol 82 (1) ◽  
pp. 63-82
Author(s):  
Takao K Watanabe ◽  
Osamu Yamaguchi ◽  
Terumi Mukai
Keyword(s):  
Drosophila Melanogaster ◽  
Balancing Selection ◽  
Local Population ◽  
Load Ratio ◽  
Average Degree ◽  
Large Cage ◽  
Degree Of Dominance ◽  
Cage Population ◽  
The Difference ◽  
Lethal Genes

ABSTRACT Five hundred and two third chromosomes were extracted from a large cage population of Drosophila melanogaster initiated two months after collection of the progenitors near Raleigh, North Carolina in 1970.—Salivary gland chromosomes of 489 chromosome lines were examined and 54 chromosomes were found to carry inversions. The inversions were classified into three polymorphic types [In(3L)P, In(3R)P, and In(3R)C] and two unique types. The polymorphic inversions were found in frequencies of 0.012, 0.088, and 0.010, respectively.—Viabilities of homozygotes and heterozygotes were examined. Chromosomes with lethals occurred with a frequency of 0.495: 0.537 in the group of inversion-carrying chromosomes and 0.490 in the group of inversion-free chromosomes. The average homozygote viability computed on the basis of an average heterozygote viability of 1.0000 was 0.3235 if lethal lines were included and 0.6290 if they were excluded. The detrimental load to lethal load ratio (D:L ratio) was 0.70 (=0.4636-0.6650). The average viability of lethal heterozygotes was significantly larger than that of lethal-free heterozygotes. It appears, however, that lethal genes in heterozygotes have deleterious effects on fitness as a whole.—The average degree of dominance for viability polygenes was estimated to be about 0.3-0.4 in lethal-free individuals and nearly zero in lethal heterozygotes. Overdominance or some form of balancing selection was suggested at some loci. The difference between the values obtained for average degree of dominance due to genetic backgrounds and superior vibaility of lethal heterozygotes (but not fitness as a whole) suggests that some epistasis or coadaptation occurs.—The results described above are similar to those obtained for the second chromosomes (Mukai and Yamaguchi 1974).

scholarly journals BALANCING SELECTION, INVERSION POLYMORPHISM AND ADAPTATION IN DDT-RESISTANT POPULATIONS OF DROSOPHILA MELANOGASTER

Genetics ◽  
1983 ◽  
Vol 105 (1) ◽  
pp. 87-104
Author(s):  
Phillip T Barnes
Keyword(s):  
Drosophila Melanogaster ◽  
Balancing Selection ◽  
Aldehyde Oxidase ◽  
Selective Advantage ◽  
Heterozygote Advantage ◽  
Allozyme Polymorphism ◽  
Frequency Dependent ◽  
Frequency Dependent Selection ◽  
Laboratory Populations ◽  
Environmental Component

ABSTRACT The modes of selection important in maintaining an inversion-allozyme polymorphism in two laboratory populations of Drosophila melanogaster were examined. The populations, 731R and J2, are highly resistant to DDT. The polymorphism involves the Standard and In(3R)P chromosomal arrangements in very strong linkage association with the AO  1 and AO  4 allozymes, respectively, of the aldehyde oxidase locus—The mean fertilities of the three karyotypes were not significantly different in 731R, but, in J2, In/In was significantly inferior to St/St and St/In. Egg-to-adult viability tests indicated very strong heterozygote advantage at all frequency combinations of the karyotypes in both populations when DDT was present. When DDT was excluded, the viabilities varied over the frequency combinations but were not inversely correlated with karyotype frequency, as predicted by balancing frequency-dependent selection. Discrete, multiple-generation experiments showed a rapid increase in heterozygote frequency to about 80% in both populations when DDT was present. Without DDT, 731R showed apparent directional selection favoring St, whereas J2 showed persistence of the polymorphism, although with extensive fluctuation.—Thus, the inversion-allozyme polymorphism is directly involved in the adaptation to a specific environmental component, DDT, and the selective advantage of the heterozygotes is the important balancing force. Balancing frequency-dependent selection was not observed, which suggests the hypothesis that this form of selection may not be involved in adaptation to novel environmental conditions.

scholarly journals The effect of an intronic polymorphism on alcohol dehydrogenase expression in Drosophila melanogaster.

Genetics ◽  
1994 ◽  
Vol 138 (2) ◽  
pp. 379-385 ◽  
Author(s):  
C C Laurie ◽  
L F Stam
Keyword(s):  
Drosophila Melanogaster ◽  
Natural Selection ◽  
Alcohol Dehydrogenase ◽  
Evolutionary Dynamics ◽  
In Vitro Mutagenesis ◽  
Allozyme Polymorphism ◽  
Selection Models ◽  
Intronic Polymorphism ◽  
Lines Of Evidence

Abstract Several lines of evidence indicate that natural selection controls the frequencies of an allozyme polymorphism at the alcohol dehydrogenase (Adh) locus in Drosophila melanogaster. However, because of associations among sequence polymorphisms in the Adh region, it is not clear whether selection acts directly (or solely) on the allozymic site. This problem has been approached by using in vitro mutagenesis to distinguish among the effects on Adh expression of individual polymorphisms. This study shows that a polymorphism within the first Adh intron (delta 1) has a significant effect on the level of ADH protein. Like the allozyme, delta 1 shows a geographic cline in frequency, indicating that it may also be a target of natural selection. These results suggest that multisite selection models may be required to understand the evolutionary dynamics of individual loci.

scholarly journals Alcohol Dehydrogenase Polymorphism of Drosophila melanogaster: Aspects of Alcohol and Temperature Variation in the Larval Environment

1982 ◽  
Vol 35 (1) ◽  
pp. 85 ◽  
Author(s):  
Stephen W McKechnie ◽  
Phillip Morgan
Keyword(s):  
Drosophila Melanogaster ◽  
Liquid Chromatography ◽  
Alcohol Dehydrogenase ◽  
Temperature Variation ◽  
Short Chain ◽  
Adult Survival ◽  
Gas Liquid Chromatography ◽  
Natural Habitats ◽  
Alcohol Mixtures

Some natural habitats of D. melanogaster larvae were examined for short-chain alcohols by gas-liquid chromatography. All habitats contained a mixture of such alcohols, although ethanol predominated and was found at concentrations ranging from 0�02 to 4�0% (v/v). Normal propanol, propan-2-01, n-butanol and methanol were nearly always present. Larval-to-adult survival was determined at three temperatures on laboratory media supplemented with alcohol mixtures similar to those found in nature, and using strains which differed in alcohol dehydrogenase genotype.

scholarly journals The Alcohol Dehydrogenase Gene Is Nested in the outspread Locus of Drosophila melanogaster

Genetics ◽  
1996 ◽  
Vol 143 (2) ◽  
pp. 897-911 ◽  
Author(s):  
S McNabb ◽  
S Greig ◽  
T Davis
Keyword(s):  
Drosophila Melanogaster ◽  
Alcohol Dehydrogenase ◽  
Pcr Amplification ◽  
Transcription Unit ◽  
Adjacent Gene ◽  
Dehydrogenase Gene ◽  
Chromosomal Breakpoints ◽  
Splicing Patterns ◽  
Somatic Musculature

Abstract This report describes the structure and expression of the outspread (osp) gene of Drosophila melanogaster. Previous work showed that chromosomal breakpoints associated with mutations of the osp locus map to both sides of the alcohol dehydrogenase gene (Adh), suggesting that Adh and the adjacent gene Adh' are nested in osp. We extended a chromosomal walk and mapped additional osp mutations to define the maximum molecular limit of osp as 119 kb. We identified a 6-kb transcript that hybridizes to osp region DNA and is altered or absent in osp mutants. Accumulation of this RNA peaks during embryonic and pupal periods. The osp cDNAs comprise two distinct classes based on alternative splicing patterns. The 5′ end of the longest cDNA was extended by PCR amplification. When hybridized to the osp walk, the 5′ extension verifies that Adh and Adh' are nested in osp and shows that osp has a transcription unit of ≥74 kb. In situ hybridization shows that osp is expressed both maternally and zygotically. In the ovary, osp is transcribed in nurse cells and localized in the oocyte. In embryos, expression is most abundant in the developing visceral and somatic musculature.

scholarly journals GENETIC AND BIOCHEMICAL BASIS OF ENZYME ACTIVITY VARIATION IN NATURAL POPULATIONS. I. ALCOHOL DEHYDROGENASE IN DROSOPHILA MELANOGASTER

Genetics ◽  
1978 ◽  
Vol 89 (2) ◽  
pp. 371-388
Author(s):  
John F McDonald ◽  
Francisco J Ayala
Keyword(s):  
Gene Regulation ◽  
Drosophila Melanogaster ◽  
Alcohol Dehydrogenase ◽  
Natural Populations ◽  
Difficult Problem ◽  
Regulatory Genes ◽  
Biochemical Basis ◽  
Evolutionary Consequence ◽  
The Third ◽  
Adh Activity

ABSTRACT Recent studies by various authors suggest that variation in gene regulation may be common in nature, and might be of great evolutionary consequence; but the ascertainment of variation in gene regulation has proven to be a difficult problem. In this study, we explore this problem by measuring alcohol dehydrogenase (ADH) activity in Drosophila melanogaster strains homozygous for various combinations of given second and third chromosomes sampled from a natural population. The structural locus (Adh) coding for ADH is on the second chromosome. The results show that: (1) there are genes, other than Adh, that affect the levels of ADH activity; (2) at least some of these "regulatory" genes are located on the third chromosome, and thus are not adjacent to the Adh locus; (3) variation exists in natural populations for such regulatory genes; (4) the effect of these regulatory genes varies as they interact with different second chromosomes; (5) third chromosomes with high-activity genes are either partially or completely dominant over chromosomes with low-activity genes; (6) the effects of the regulatory genes are pervasive throughout development; and (7) the third chromosome genes regulate the levels of ADH activity by affecting the number of ADH molecules in the flies. The results are consistent with the view that the evolution of regulatory genes may play an important role in adaptation.

scholarly journals The Rate of Mutation and the Homozygous and Heterozygous Mutational Effects for Competitive Viability: A Long-Term Experiment With Drosophila melanogaster

Genetics ◽  
2001 ◽  
Vol 158 (2) ◽  
pp. 681-693 ◽  
Author(s):  
David Chavarrías ◽  
Carlos López-Fanjul ◽  
Aurora García-Dorado
Keyword(s):  
Drosophila Melanogaster ◽  
Minimum Distance ◽  
Deleterious Mutations ◽  
Regression Estimate ◽  
Term Experiment ◽  
Degree Of Dominance ◽  
Long Term Experiment ◽  
Rate Of Decline ◽  
Good Agreement

Abstract The effect of 250 generations of mutation accumulation (MA) on the second chromosome competitive viability of Drosophila melanogaster was analyzed both in homozygous and heterozygous conditions. We used full-sib MA lines, where selection hampers the accumulation of severely deleterious mutations but is ineffective against mildly deleterious ones. A large control population was simultaneously evaluated. Competitive viability scores, unaffected by the expression of mutations in heterozygosis, were obtained relative to a Cy/L2 genotype. The rate of decline in mean ΔM ≈ 0.1% was small. However, that of increase in variance ΔV ≈ 0.08 × 10-3 was similar to the values obtained in previous experiments when severely deleterious mutations were excluded. The corresponding estimates of the mutation rate λ ≥ 0.01 and the average effect of mutations E(s) ≤ 0.08 are in good agreement with Bateman-Mukai and minimum distance estimates for noncompetitive viability obtained from the same MA lines after 105 generations. Thus, competitive and noncompetitive viability show similar mutational properties. The regression estimate of the degree of dominance for mild-to-moderate deleterious mutations was ∼0.3, suggesting that the pertinent value for new unselected mutations should be somewhat smaller.

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