Genetic analysis of Drosophila vitellogenesis: A molecular weight variant of yolk polypeptide-2 in Drosophila simulans

1980 ◽  
Vol 178 (2) ◽  
pp. 253-260 ◽  
Author(s):  
J. H. Postlethwait
Keyword(s):  
Molecular Weight ◽  
Genetic Analysis ◽  
Drosophila Simulans

scholarly journals A Quantitative Genetic Analysis of Male Sexual Traits Distinguishing the Sibling Species Drosophila simulans and D. sechellia

Genetics ◽  
1999 ◽  
Vol 153 (4) ◽  
pp. 1683-1699 ◽  
Author(s):  
Stuart J Macdonald ◽  
David B Goldstein
Keyword(s):  
Genetic Analysis ◽  
Sibling Species ◽  
Reproductive Traits ◽  
Drosophila Simulans ◽  
Directional Selection ◽  
Posterior Lobe ◽  
Sex Comb ◽  
Tooth Number ◽  
Comb Tooth ◽  
Shape And Size

Abstract A quantitative trait locus (QTL) genetic analysis of morphological and reproductive traits distinguishing the sibling species Drosophila simulans and D. sechellia was carried out in a backcross design, using 38 markers with an average spacing of 8.4 cM. The direction of QTL effects for the size of the posterior lobe was consistent across the identified QTL, indicating directional selection for this trait. Directional selection also appears to have acted on testis length, indicating that sexual selection may have influenced many reproductive traits, although other forms of directional selection cannot be ruled out. Sex comb tooth number exhibited high levels of variation both within and among isofemale lines and showed no evidence for directional selection and, therefore, may not have been involved in the early speciation process. A database search for genes associated with significant QTL revealed a set of candidate loci for posterior lobe shape and size, sex comb tooth number, testis length, tibia length, and hybrid male fertility. In particular, decapentaplegic (dpp), a gene known to influence the genital arch, was found to be associated with the largest LOD peak for posterior lobe shape and size.

scholarly journals Genetics of sexual isolation in male hybrids of Drosophila simulans and D. mauritiana

1996 ◽  
Vol 68 (3) ◽  
pp. 211-220 ◽  
Author(s):  
Jerry A. Coyne
Keyword(s):  
Genetic Analysis ◽  
Y Chromosome ◽  
Sibling Species ◽  
Previous Analysis ◽  
Sexual Isolation ◽  
Drosophila Simulans

SummarySexual isolation between the sibling species D. simulans and D. mauritiana is due largely to the rejection of D. simulans males by D. mauritiana females. Genetic analysis shows that genes on the X and third chromosomes contribute to the differences between males causing sexual isolation, while the Y chromosome, second chromosome and cytoplasm have no effect. These chromosome effects differ from those observed in a previous analysis of sexual isolation in hybrid females, implying that different genes cause sexual isolation in the two sexes.

Comparative study of the beta-lactamase activity found in Achromobacter

1983 ◽  
Vol 29 (7) ◽  
pp. 819-826 ◽  
Author(s):  
Roger Levesque ◽  
Robert Letarte ◽  
Jean-Claude Pechère
Keyword(s):  
Molecular Weight ◽  
Genetic Analysis ◽  
Gram Negative Bacteria ◽  
Beta Lactamase ◽  
Gram Negative ◽  
Chromosomal Origin ◽  
Clinical Interest ◽  
High Level ◽  
Hydrolysis Of

A survey of 21 clinical isolates of Achromobacter species demonstrated a high level of β-lactamase activity in all strains tested. The β-lactamases were characterized by isoelectric focusing, purification by affinity chromatography, determination of molecular weight, immunological identity, and genetic analysis. At least three distinct patterns of β-lactamases were found in 19 strains. The kinetic values Km and Vmax measured by a microacidimetric method showed that all three types of enzymes are cephalosporinases and did not hydrolyse oxacillin, cloxacillin, and methicillin. Two of the three types of cephalosporinases studied, namely MULB 901 (isoelectric point (pI) 7.4) and MULB 905 (pI 9.3) are enzymes mediated by genes of chromosomal origin. The MULB 906 (pI 8.1) enzyme, however, which has been previously shown to be mediated by an 8.2 MDal nonconjugative plasmid, showed hydrolysis of cefoxitime, cefotaxin, and moxalactam by the bioassay. In all cases, β-lactamase synthesis appeared constitutive. This study confirms that β-lactamase activity is commonly found in Achromobacter and that these enzymes are different and of clinical interest when compared with those observed in other Gram-negative bacteria.

The genetic analysis of puffing in polytene chromosomes of Drosophila

1970 ◽  
Vol 176 (1044) ◽  
pp. 319-327 ◽  
Keyword(s):  
Drosophila Melanogaster ◽  
Salivary Gland ◽  
Genetic Analysis ◽  
Structural Gene ◽  
Chromosome Aberrations ◽  
Polytene Chromosomes ◽  
Drosophila Simulans ◽  
Salivary Gland Chromosome ◽  
Observed Behaviour

The characteristics of several mutants of Drosophila melanogaster and Drosophila simulans lacking particular salivary gland chromosome puffs are described. On the basis of their observed behaviour in heterozygotes these puff mutants can be classified into puff structural gene and puff regulating gene mutants. Other types of mutation affecting the larval and prepupal puffing cycle include lethals, mutants controlling puff size, and chromosome aberrations which divide a puff into two separate puffs.

scholarly journals GENETIC ANALYSIS OF PHOTOTACTIC BEHAVIOR IN DROSOPHILA SIMULANS

Genetics ◽  
1977 ◽  
Vol 85 (2) ◽  
pp. 273-278
Author(s):  
Therese Ann Markow ◽  
Weber L Smith
Keyword(s):  
Genetic Analysis ◽  
Drosophila Simulans ◽  
Drosophila Species ◽  
Phototactic Behavior ◽  
Polygenic Trait

ABSTRACT Phototaxis mazes have been employed to select photopositive and photonegative strains of Drosophila simulans. The results suggest that phototactic behavior in D. simulans, as in other Drosophila species, is a polygenic trait. Hybridization using divergent strains revealed that the genes controlling negative phototactic behavior in D. simulansare autosomal, as opposed to D. melanogaster in which negative phototactic behavior is known to be very strongly sex-linked.

scholarly journals Genetics of sexual isolation in females of the Drosophila simulans species complex

1992 ◽  
Vol 60 (1) ◽  
pp. 25-31 ◽  
Author(s):  
Jerry A. Coyne
Keyword(s):  
Genetic Analysis ◽  
X Chromosome ◽  
Genetic Similarity ◽  
Species Complex ◽  
Sexual Isolation ◽  
Drosophila Simulans ◽  
Genetic Studies ◽  
Dominance Relationships ◽  
Behavioural Interactions ◽  
Total Divergence

SummaryGenetic analysis of hybrids between Drosophila simulans and D. sechellia shows that sexual isolation in females is caused by at least two genes, one on each major autosome, while the X chromosome has no effect. These results are similar to those of a previous study of hybrids between D. simulans and another sibling species, D. mauritiana. In this latter hybridization, each arm of the second chromosome carries genes causing sexual isolation in females, implying a total divergence of at least three loci. The genetic similarity between the D. simulans/D. mauritiana and D. simulans/D. sechellia hybridizations probably results from independent evolution and not phylogenetic artifacts, because the dominance relationships and behavioural interactions differ between the two hybridizations. The lack of an X-chromosome effect on sexual isolation contrasts with genetic studies of post-zygotic reproductive isolation, which invariably show strong effects of this chromosome.

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