Spontaneous and induced activation of genes affecting the phenotypic expression of glucose 6-phosphate dehydrogenase in Daphnia pulex

1983 ◽  
Vol 189 (3) ◽  
pp. 485-489 ◽  
Author(s):  
A. O. Ruvinsky ◽  
Yu. I. Lobkov ◽  
D. K. Belyaev





2004 ◽  
Vol 32 (1) ◽  
pp. 112-117 ◽  
Author(s):  
R VANWIJK ◽  
E HUIZINGA ◽  
I PRINS ◽  
A KORS ◽  
G RIJKSEN ◽  
...  


1992 ◽  
Vol 49 (1) ◽  
pp. 159-165 ◽  
Author(s):  
Charles W. Ramcharan ◽  
Stanley I. Dodson ◽  
Jason Lee

Exposure to chemical exudates from the planktonic invertebrate predator Chaohorus americanus causes the prey Daphnia pulex to migrate upwards in the water column of laboratory experimental chambers. This behavior is an antipredator defense that results in spatial separation of Daphnia from Chaoborus, since this predator tends to remain near the bottom of the chambers. We test the effects of prey vulnerability, genotype, prior exposure to predators, and predator density on antipredator behavior of D. pulex. To study differences in vulnerability, we compared two genotypes of Daphnia that differed in their ability to produce a morphological defense (growth of neck spines) when exposed to Chaohorus chemical. Overall, behavioral responses to Chaoborus were stronger at higher predator densities. Juvenile Daphnia that are most vulnerable to Chaoborus predation had stronger responses than the less vulnerable adults. Neither genetically determined ability to produce neck spines nor phenotypic expression of neck spines affected strength of antipredator behavior. Vertical migration to avoid Chaoborus may have an ecological cost. Presence of Chaoborus reduced ingestion rates of juvenile Daphnia at low food levels (5 × 103 algal cells∙mL−1). Feeding experiments also showed differences in feeding characteristics of two different clones of D. pulex.



1990 ◽  
Vol 56 (2-3) ◽  
pp. 157-162 ◽  
Author(s):  
Jack Favor ◽  
Walter Pretsch

SummaryLinkage data relative to the markers tabby and glucose-6-phosphate dehydrogenase are presented to locate X-linked cataract (Xcat) in the distal portion of the mouse X-chromosome between jimpy and hypophosphatemia. The human X-linked cataract-dental syndrome, Nance–Horan Syndrome, also maps closely to human hypophosphatemia and would suggest homology between mouse Xcat and human Nance-Horan Syndrome genes. In hemizygous males and homozygous females penetrance is complete with only slight variation in the degree of expression. Phenotypic expression in Xcat heterozygous females ranges from totally clear to totally opaque lenses. The phenotypic expression between the two lenses of a heterozygous individual could also vary between totally clear and totally opaque lenses. However, a correlation in the degree of expression between the eyes of an individual was observed. A variegated pattern of lens opacity was evident in female heterozygotes. Based on these observations, the site of gene action for the Xcat locus is suggested to be endogenous to the lens cells and the precursor cell population of the lens is concluded to be small. The identification of an X-linked cataract locus is an important contribution to the estimate of the number of mutable loci resulting in cataract, an estimate required so that dominant cataract mutagenesis results may be expressed on a per locus basis. The Xcat mutation may be a useful marker for a distal region of the mouse X-chromosome which is relatively sparsely marked and the X-linked cataract mutation may be employed in gene expression and lens development studies.





1969 ◽  
Vol 61 (1_Suppl) ◽  
pp. S46
Author(s):  
Georg W. Oertel ◽  
Peter Menzel ◽  
Ilse Rebelein


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