scholarly journals Direct and correlated responses to selection for desiccation resistance: a comparison of Drosophila melanogaster and D. simulans

1993 ◽  
Vol 6 (5) ◽  
pp. 643-657 ◽  
Author(s):  
Ary A. Hoffmann ◽  
P. A. Parsons
1998 ◽  
Vol 201 (21) ◽  
pp. 2945-2952 ◽  
Author(s):  
A E Williams ◽  
M R Rose ◽  
T J Bradley

We conducted concurrent measurements of rates of CO2 and H2O release from individual fruit flies Drosophila melanogaster taken from populations subjected to three different selective regimes: (1) populations selected for resistance to desiccation (D flies); (2) populations maintained as their controls (C flies); and (3) the ancestral populations of the D and C populations (O flies). In the D flies, water loss rates were significantly reduced, the standard error of the regression (SER) of the CO2 release pattern measured over the survival period of the flies was increased, and the ratio of CO2 loss to H2O loss (VCO2/VH2O) was increased. Correlations across all 15 populations from the three selection treatments indicate that survival time was negatively correlated with water loss rate, positively correlated with the SER of CO2 release and positively correlated with the VCO2/VH2O ratio. We did not, however, find a significant correlation between the SER of CO2 release and rates of water loss or the VCO2/VH2O ratio.


Genetics ◽  
1976 ◽  
Vol 84 (2) ◽  
pp. 333-351
Author(s):  
Margaret G Kidwell ◽  
J F Kidwell

ABSTRACT Two-way selection for male recombination over seven intervals of the third chromosome in Drosophila melanogaster was practiced for nine generations followed by relaxed selection for five generations. Significant responses in both directions were observed but these mainly occurred in early generations in the low line and in later generations in the high line. Divergence of male recombination frequencies between the two selection lines was not restricted to any specific region but occurred in every measured interval of the chromosome. However, right-arm intervals showed a more pronounced response than either left-arm intervals or the centromeric region. Correlated responses in sterility and distortion of transmission ratios occurred as a result of selection for male recombination. Cluster distributions of male recombinants suggested a mixture of meiotic and late gonial events but relative map distances more closely resembled those of the salivary chromosome than standard meiotic or mitotic distances. Patterns of male recombination over time in both second and third chromosomes strongly suggested a major effect associated with the presence of third chromosomes from the Harwich strain. Evidence was also found for modifiers with relatively small effects located in other regions of the genome. The overall results are interpreted in terms of a two-component model of hybrid dysgenesis.


1999 ◽  
Vol 74 (1) ◽  
pp. 43-54 ◽  
Author(s):  
LINDA PARTRIDGE ◽  
ROSALIE LANGELAN ◽  
KEVIN FOWLER ◽  
BAS ZWAAN ◽  
VERNON FRENCH

Correlated responses to artificial selection on body size in Drosophila melanogaster were investigated, to determine how the changes in size were produced during development. Selection for increased thorax length was associated with an increase in larval development time, an extended growth period, no change in growth rate, and an increased critical larval weight for pupariation. Selection for reduced thorax length was associated with reduced growth rate, no change in duration of larval development and a reduced critical larval weight for pupariation. In both lines selected for thorax length and lines selected for wing area, total body size changed in the same direction as the artificially selected trait. In large selection lines of both types, the increase in size was achieved almost entirely by an increase in cell number, while in the small lines the decrease in size was achieved predominantly by reduced cell size, and also by a reduction in cell number. The implications of the results for evolutionary-genetic change in body size in nature are discussed.


2007 ◽  
Vol 32 (4) ◽  
pp. 322-327 ◽  
Author(s):  
BRENT J. SINCLAIR ◽  
SEAN NELSON ◽  
THERESA L. NILSON ◽  
STEPHEN P. ROBERTS ◽  
ALLEN G. GIBBS

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