Studies on Inbred Strains of Drosophila melanogaster

1965 ◽  
Vol 99 (909) ◽  
pp. 495-510 ◽  
Author(s):  
Bruce Wallace ◽  
Carol Madden
1983 ◽  
Vol 61 (5) ◽  
pp. 1152-1155 ◽  
Author(s):  
Nicole Cadieu

When larval competition in Drosophila melanogaster is prevented, survival up to imaginal emergence in two inbred strains and their reciprocal hybrids seems to depend on (i) a maternal influence (possibly due to cytoplasmic factors), (ii) the state of inbreeding or outbreeding of the progeny. The study of the death rate during development demonstrates that the maternal effect can be detected at every stage of the preimaginal life (embryo, larva, and pupa). On the other hand heterosis is superimposed on the maternal effect mainly during larval life, the viability for the hybrid larvae being higher than the average of the two parental strains.


2016 ◽  
Vol 113 (4) ◽  
pp. 1014-1019 ◽  
Author(s):  
Justin B. Lack ◽  
Matthew J. Monette ◽  
Evan J. Johanning ◽  
Quentin D. Sprengelmeyer ◽  
John E. Pool

In higher organisms, the phenotypic impacts of potentially harmful or beneficial mutations are often modulated by complex developmental networks. Stabilizing selection may favor the evolution of developmental canalization—that is, robustness despite perturbation—to insulate development against environmental and genetic variability. In contrast, directional selection acts to alter the developmental process, possibly undermining the molecular mechanisms that buffer a trait’s development, but this scenario has not been shown in nature. Here, we examined the developmental consequences of size increase in highland Ethiopian Drosophila melanogaster. Ethiopian inbred strains exhibited much higher frequencies of wing abnormalities than lowland populations, consistent with an elevated susceptibility to the genetic perturbation of inbreeding. We then used mutagenesis to test whether Ethiopian wing development is, indeed, decanalized. Ethiopian strains were far more susceptible to this genetic disruption of development, yielding 26 times more novel wing abnormalities than lowland strains in F2 males. Wing size and developmental perturbability cosegregated in the offspring of between-population crosses, suggesting that genes conferring size differences had undermined developmental buffering mechanisms. Our findings represent the first observation, to our knowledge, of morphological evolution associated with decanalization in the same tissue, underscoring the sensitivity of development to adaptive change.


Genetics ◽  
1994 ◽  
Vol 136 (3) ◽  
pp. 937-951 ◽  
Author(s):  
T F Mackay ◽  
J D Fry ◽  
R F Lyman ◽  
S V Nuzhdin

Abstract Replicated divergent artificial selection for abdominal and sternopleural bristle number from a highly inbred strain of Drosophila melanogaster resulted in an average divergence after 125 generations of selection of 12.0 abdominal and 8.2 sternopleural bristles from the accumulation of new mutations affecting bristle number. Responses to selection were highly asymmetrical, with greater responses for low abdominal and high sternopleural bristle numbers. Estimates of VM, the mutational variance arising per generation, based on the infinitesimal model and averaged over the responses to the first 25 generations of selection, were 4.32 x 10(-3) VE for abdominal bristle number and 3.66 x 10(-3) VE for sternopleural bristle number, where VE is the environmental variance. Based on 10 generations of divergent selection within lines from generation 93, VM for abdominal bristle number was 6.75 x 10(-3) VE and for sternopleural bristle number was 5.31 x 10(-3) VE. However, estimates of VM using the entire 125 generations of response to selection were lower and generally did not fit the infinitesimal model largely because the observed decelerating responses were not compatible with the predicted increasing genetic variance over time. These decelerating responses, periods of response in the opposite direction to artificial selection, and rapid responses to reverse selection all suggest new mutations affecting bristle number on average have deleterious effects on fitness. Commonly observed periods of accelerated responses followed by long periods of stasis suggest a leptokurtic distribution of mutational effects for bristles.


1966 ◽  
Vol 19 (4) ◽  
pp. 587 ◽  
Author(s):  
PA Parsons

Longevity in four inbred strains and their hybrids has been studied at two temperatures, 29�5 and 25�C. Heterosis was found at both temperatures but was more extreme at 29� 5�C, which is a very unfavourable environment for D. melanogaster. This observation has its parallel in observations on various fitness factors in several organisms. At 29� 5�C there was more variability of a genotypic nature between the hybrids than at 25�C, perhaps because the adaptation to this unfavourable environment depencls on rather special gene combinations. Thus longevity varies between genotypes, but the pattern of variation depends in an intimate way on the environment.


2015 ◽  
Author(s):  
Nandita R. Garud ◽  
Dmitri A. Petrov

The extent to which selection and demography impact patterns of genetic diversity in natural populations of Drosophila melanogaster is yet to be fully understood. We previously observed that the pattern of LD at scales of ~10 kb in the Drosophila Genetic Reference Panel (DGRP), consisting of 145 inbred strains from Raleigh, North Carolina, measured both between pairs of sites and as haplotype homozygosity, is elevated above neutral demographic expectations. Further, we demonstrated that signatures of strong and recent soft sweeps are abundant. However, the extent to which this pattern is specific to this derived and admixed population is unknown. Neither is it clear whether such a pattern may have arisen as a consequence of the extensive inbreeding performed to generate the DGRP data. Here we analyze > 100 fully sequenced strains from Zambia, an ancestral population to the Raleigh population, that has experienced little to no admixture and was generated by sequencing haploid embryos rather than inbred strains. This data set allows us to determine whether patterns of elevated LD and signatures of abundant soft sweeps are generic to multiple populations of D. melanogaster or whether they are generated either by inbreeding, bottlenecks or admixture in the DGRP dataset. We find an elevation in long-range LD and haplotype homozygosity in the Zambian dataset, confirming the result from the DGRP data set. This elevation in LD and haplotype structure remains even after controlling for many sources of LD in the data including genomic inversions, admixture, population substructure, close relatedness of individual strains, and recombination rate variation. Furthermore, signatures of partial soft sweeps similar to those found in the DGRP are common in Zambia. These results suggest that while the selective forces and sources of adaptive mutations may differ in Zambia and Raleigh, elevated long-range LD and signatures of soft sweeps are generic in D. melanogaster.


2016 ◽  
Vol 12 (12) ◽  
pp. 20160657 ◽  
Author(s):  
Mirjam Appel ◽  
Claus-Jürgen Scholz ◽  
Samet Kocabey ◽  
Sinead Savage ◽  
Christian König ◽  
...  

A painful event establishes two opponent memories: cues that are associated with pain onset are remembered negatively, whereas cues that coincide with the relief at pain offset acquire positive valence. Such punishment- versus relief-memories are conserved across species, including humans, and the balance between them is critical for adaptive behaviour with respect to pain and trauma. In the fruit fly, Drosophila melanogaster as a study case, we found that both punishment- and relief-memories display natural variation across wild-derived inbred strains, but they do not covary, suggesting a considerable level of dissociation in their genetic effectors. This provokes the question whether there may be heritable inter-individual differences in the balance between these opponent memories in man, with potential psycho-clinical implications.


Evolution ◽  
1992 ◽  
Vol 46 (2) ◽  
pp. 300 ◽  
Author(s):  
Trudy F. C. Mackay ◽  
Richard F. Lyman ◽  
Michael S. Jackson ◽  
Christophe Terzian ◽  
William G. Hill

Genetics ◽  
1994 ◽  
Vol 137 (2) ◽  
pp. 509-511 ◽  
Author(s):  
B D Latter ◽  
J A Sved

Abstract We have analyzed the results from a range of procedures designed to measure the fitness under competitive conditions of inbred strains of Drosophila melanogaster, specifically strains which are homozygous for chromosome 2. All methods show a substantial reduction in fitness, ranging from an estimated 70-80% for single generation competition tests to 80-90% for a multiple generation population cage procedure. Furthermore, inbreeding through brother-sister mating reduces fitness by a comparable amount when allowance is made for the expected degree of homozygosity.


1969 ◽  
Vol 47 (3) ◽  
pp. 313-321
Author(s):  
L. Butler

Four inbred strains of flies have been maintained by brother × sister mating since November, 1963. Counts of production per vial were made at 14 days, and the flies from the most productive vial were used as the parents of the next generation. For analysis the data were separated into three groups: vials with no production (blanks), vials with less than 20 flies (low production), and those with over 20 flies. The number of blanks did not change significantly in strain A but did show significant decreases in strains B and D. Until generation 60 the number of blanks per generation was not distributed in a Poisson series, but after this generation it was. The number of vials with low production was high in all strains for the first 20 generations and then decreased in widely different generations for each strain.Changes took place in all four strains but by different mechanisms. In strain A there was no increase in range, but the mode moved from 40 to 150 flies per vial and the proportion of low productive vials fell from 15% to 2% per generation. In strain D the low production vials fell from 22% to 6% and there was an extension of the range. Each of the strains shows definite trends of increase and decrease which last from 3 to 30 generations, and vary in slope from 0.3 to 13.8 flies per vial per generation. While we cannot determine how much or how many of these slopes are environmental, it can be argued that since many of the slopes of the four strains are not correlated, part of the cause is genetic. The changes in the direction of the trends show that phenotypic selection in small populations was not effective in accumulating and exploiting mutations for greater productivity.


1970 ◽  
Vol 52 (2) ◽  
pp. 419-436
Author(s):  
KARL GEORGE GÖTZ

1. The optomotor control of orientation and locomotion in the fruitfly Drosophila melanogaster requires the conveyance of information from distinct movement detectors in the visual system to distinct movement effectors in the motor system. Abnormalities of the optomotor control system have been found occasionally in Drosophila. 2. The abnormal flies can be isolated from population samples by appropriate fractionation according to the magnitude and the sign of the optomotor responses. A cyclically operating machine was used to fractionate two inbred strains, w+ and wα, which possess different alleles on the white-locus of their X-chromosomes. 3. Movements of an artificial visual environment elicit similar orientation-control responses, but antagonistic locomotion-control responses in the two strains. The responses depend on various parameters and may even change with habituation to the stimulus. However, the application of selection pressure through eight generations has little if any effect on the different optomotor behaviour of the inbred strains.


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