Female characteristics in theDrosophila melanogaster-sigma virus system in natural populations from Languedoc (southern France)

1994 ◽  
Vol 135 (1-2) ◽  
pp. 29-42 ◽  
Author(s):  
A. Fleuriet
Keyword(s):  
Natural Populations ◽  
Southern France ◽  
Sigma Virus ◽  
Virus System

scholarly journals EXTRACHROMOSOMAL INHERITANCE OF CARBON DIOXIDE SENSITIVITY IN THE MOSQUITO CULEX QUINQUEFASCIATUS

Genetics ◽  
1983 ◽  
Vol 104 (4) ◽  
pp. 649-659
Author(s):  
Donald A Shroyer ◽  
Leon Rosen
Keyword(s):  
Carbon Dioxide ◽  
Culex Quinquefasciatus ◽  
Natural Populations ◽  
Infectious Agent ◽  
Maternal Transmission ◽  
Co2 Sensitivity ◽  
Laboratory Colony ◽  
F1 Progeny ◽  
Extrachromosomal Inheritance ◽  
Sigma Virus

ABSTRACT Mosquitoes from a laboratory colony of Culex quinquefasciatus from Matsu Island, China, develop irreversible paralytic symptoms after exposure to carbon dioxide at 1°. This CO2 sensitivity is caused by an inherited infectious agent, probably a virus. Crossing studies between CO2-sensitive and -resistant mosquitoes showed that the sensitivity trait is inherited extrachromosomally in a fashion strictly analogous to the hereditary transmission of sigma virus in Drosophila melanogaster. Sensitivity could be maintained through maternal transmission alone, despite nine generations of backcrossing of "stabilized" CO2-sensitive females to males from a resistant strain. CO2-sensitive males crossed to resistant females transmitted sensitivity to a portion of their F1 progeny, and only the female F1 sensitives were capable of further hereditary transmission.—Matsu, or a very similar hereditary infectious agent, is common in natural populations of Cx. quinquefasciatus on Oahu, Hawaii. Fifty-nine percent of the families reared from field-collected egg rafts contained CO2-sensitive mosquitoes, and some families contained only sensitive mosquitoes.

scholarly journals POLYMORPHISM OF THE HEREDITARY SIGMA VIRUS IN NATURAL POPULATIONS OF DROSOPHILA MELANOGASTER

Genetics ◽  
1980 ◽  
Vol 95 (2) ◽  
pp. 459-465
Author(s):  
Annie Fleuriet
Keyword(s):  
Drosophila Melanogaster ◽  
Natural Populations ◽  
Common Type ◽  
Co2 Sensitivity ◽  
Genetic Types ◽  
Sigma Virus

ABSTRACT Previous studies have shown that, in natural French populations of Drosophila melanogaster, 10 to 20% of the flies are infected by the noncontagious, hereditary rhabdovirus sigma responsible for CO2 sensitivity. These populations are also polymorphic for two alleles [ref(2)Po and ref(2)Pp of a gene for resistance to the sigma virus. Evidence is given here that two viral genetic types, differing in their response to the ref(2)Pp allele, are present in these populations of flies; the most common type is only slightly sensitive to the ref(2)Pp allele.

scholarly journals Disease association mapping in Drosophila can be replicated in the wild

2010 ◽  
Vol 6 (5) ◽  
pp. 666-668 ◽  
Author(s):  
Lena Wilfert ◽  
Francis M. Jiggins
Keyword(s):  
Association Mapping ◽  
Linkage Mapping ◽  
Complex Traits ◽  
Wild Population ◽  
Natural Populations ◽  
Model Systems ◽  
In The Wild ◽  
Genotype Interaction ◽  
Limited Power ◽  
Sigma Virus

Association and linkage mapping have become important tools in understanding the genetics of complex traits, including diseases in humans. As the success of association mapping is reduced by small effect sizes and limited power, linkage studies in laboratory-based model systems are still heavily used. But whether the results of these studies can be replicated in natural populations has been questioned. Here, we show that a polymorphism in the gene ref ( 2 ) P , which had previously been linked to sigma virus resistance in Drosophila melanogaster under laboratory conditions, also provides resistance against the virus in female flies in a wild population in the field. This genetic association is thus upheld in spite of a known genotype-by-genotype interaction and environmental variation.

High-voltage electron microscopy of maxillary gland of spirochete-infected brine shrimp: lesion of efferent tubule

1988 ◽  
Vol 46 ◽  
pp. 362-363
Author(s):  
G. E. Tyson ◽  
M. J. Song
Keyword(s):  
Electron Microscopy ◽  
High Voltage ◽  
Brine Shrimp ◽  
Natural Populations ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
High Voltage Electron Microscopy ◽  
Voltage Electron ◽  
High Voltage Electron ◽  
Infected Adult

Natural populations of the brine shrimp, Artemia, may possess spirochete- infected animals in low numbers. The ultrastructure of Artemia's spirochete has been described by conventional transmission electron microscopy. In infected shrimp, spirochetal cells were abundant in the blood and also occurred intra- and extracellularly in the three organs examined, i.e. the maxillary gland (segmental excretory organ), the integument, and certain muscles The efferent-tubule region of the maxillary gland possessed a distinctive lesion comprised of a group of spirochetes, together with numerous small vesicles, situated in a cave-like indentation of the base of the tubule epithelium. in some instances the basal lamina at a lesion site was clearly discontinuous. High-voltage electron microscopy has now been used to study lesions of the efferent tubule, with the aim of understanding better their three-dimensional structure.Tissue from one maxillary gland of an infected, adult, female brine shrimp was used for HVEM study.

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