RADIOSENSITIVITY OF THE EXTRA-LARGE (XL) MUTANT OF TRIBOLIUM CONFUSUM (COLEOPTERA: TENEBRIONIDAE)

1978 ◽  
Vol 110 (9) ◽  
pp. 907-912 ◽  
Author(s):  
H. H. Vardell ◽  
J. H. Brower ◽  
C. E. Shelby

AbstractThe radiosensitivity of a wild-type (+/+) laboratory strain of Tribolium confusum Jacquelin duVal was compared with that of an extra-large (xl/xl) strain known to differ in only a single locus. Differences in both longevity and fecundity between the two strains after irradiation were very highly significant (p < 0.001), but real differences between strains in these biological characteristics may have produced the differential response. When differences in longevity and fecundity were corrected for the unirradiated control, there were only minor differences in response between the two strains. Thus, physical size alone apparently did not greatly influence the comparative radiosensitivity for the two strains of this species.

1975 ◽  
Vol 17 (4) ◽  
pp. 609-613 ◽  
Author(s):  
H. H. Vardell ◽  
J. H. Brower

A new mutant of Tribolium confusum Jacquelin duVal (Coleoptera: Tenebrionidae), extra-large (designated xl), was isolated in mating competition tests with red-eye (re) and wild-type (+). Crosses showed that it was autosomal recessive gene with subvital effects. The pupal weights averaged 6.1 and 7.3 mg for males and females, respectively, about twice the weights of the ancestral wild-type. The generation time (egg to adult) was approximately 8 to 9 weeks compared with about 4 weeks for the wild-type. This increase resulted from a lengthening of the larval stage since the durations of the egg and pupal stages were within the ranges of the wild-type. Mean longevity of xl males and females was reduced to 8.5 and 6.0 weeks, respectively at 26.7 ± 1 °C and 60% RH.


Genetics ◽  
1997 ◽  
Vol 146 (3) ◽  
pp. 871-880
Author(s):  
Robin R Preston ◽  
Jocelyn A Hammond

Three mutant strains of Paramecium tetraurelia with an enhanced sensitivity to magnesium have been isolated. These new “Chameleon” mutants result from partial- or codominant mutations at a single locus, Cha. Whereas the wild type responded to 5 mm Mg2+ by swimming backward for 10–15 sec, Cha mutants responded with ∼30 sec backward swimming. Electrophysiological analysis suggested that this behavior may be caused by slowing in the rate at which a Mg2+-specific ion conductance deactivates following membrane excitation. This would be consistent with an observed increase in the sensitivity of Cha mutants to nickel poisoning, since Ni2+ is also able to enter the cell via this pathway. More extensive behavioral analysis showed that Cha cells also overresponded to Na+, but there was no evidence for a defect in intracellular Ca2+ homeostasis that might account for a simultaneous enhancement of both the Mg2+ and Na+ conductances. The possibility that the Cha locus may encode a specific regulator of the Mg2+- and Na+-permeabilities is considered.


Genetics ◽  
1972 ◽  
Vol 70 (4) ◽  
pp. 595-610
Author(s):  
Ray Moree

ABSTRACT The viability effects of chromosomes from an old and from a new laboratory strain of D. melanogaster were studied in eight factorial combinations and at two heterozygosity levels. The combinations were so constructed that heterozygosity level could be varied in the third chromosomes of the carriers of a homozygous lethal marker, in the third chromosomes of their wild-type segregants, and in the genetic backgrounds of both. Excluding the effect of the marker and the exceptional outcomes of two of the combinations, and taking into account both large and small deviations from theoretical expectation, the following summary is given as the simplest consistent explanation of the results: 1) If total heterozygosities of two segregant types tend toward equality their viabilities tend toward equality also, whether background heterozygosity is high or low; if background heterozygosities is higher the tendency toward equality is slightly greater. 2) If total heterozygosity of two segregant types are unequal the less heterozygous type has the lower viability; the difference is more pronounced when background heterozygosity is low, less when it is high. 3) Differences between segregant viabilities are correlated with differences between the total heterozygosities of the two segregants; genetic background is effective to the extent, and only to the extent, that it contributes to the magnitude of this difference. This in turn appears to underlie, at least partly, the expression of a pronounced interchromosomal epistasis. Thus in this study viability is seen to depend upon both the quantity and distribution of heterozygosity, not only among the chromosomes of an individual but among the individuals of a given combination as well.


2008 ◽  
pp. 3110-3110
Author(s):  
Norman C. Leppla ◽  
Bastiaan M. Drees ◽  
Allan T. Showler ◽  
John L. Capinera ◽  
Jorge E. Peña ◽  
...  

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