scholarly journals speck, First Identified in Drosophila melanogaster in 1910, Is Encoded by the Arylalkalamine N-Acetyltransferase (AANAT1) Gene

2020 ◽  
Vol 10 (9) ◽  
pp. 3387-3398 ◽  
Author(s):  
Eric P Spana ◽  
Amanda B Abrams ◽  
Katharine T Ellis ◽  
Jason C Klein ◽  
Brandon T Ruderman ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Research Effort ◽  
Body Color ◽  
Melanin Production ◽  
Dorsal Portion ◽  
Exon 1 ◽  
Insertion Allele ◽  
Melanin Pathway ◽  
Thomas Hunt Morgan

Abstract The pigmentation mutation speck is a commonly used recombination marker characterized by a darkly pigmented region at the wing hinge. Identified in 1910 by Thomas Hunt Morgan, speck was characterized by Sturtevant as the most “workable” mutant in the rightmost region of the second chromosome and eventually localized to 2-107.0 and 60C1-2. Though the first speck mutation was isolated over 110 years ago, speck is still not associated with any gene. Here, as part of an undergraduate-led research effort, we show that speck is encoded by the Arylalkylamine N-acetyltransferase 1 (AANAT1) gene. Both alleles from the Morgan lab contain a retrotransposon in exon 1 of the RB transcript of the AANAT1 gene. We have also identified a new insertion allele and generated multiple deletion alleles in AANAT1 that all give a strong speck phenotype. In addition, expression of AANAT1 RNAi constructs either ubiquitously or in the dorsal portion of the developing wing generates a similar speck phenotype. We find that speck alleles have additional phenotypes, including ectopic pigmentation in the posterior pupal case, leg joints, cuticular sutures and overall body color. We propose that the acetylated dopamine generated by AANAT1 decreases the dopamine pool available for melanin production. When AANAT1 function is decreased, the excess dopamine enters the melanin pathway to generate the speck phenotype.

scholarly journals speck, first identified in Drosophila melanogaster in 1910, is encoded by the Arylalkalamine N-acetyltransferase (AANAT1) gene

2019 ◽  
Author(s):  
Eric P Spana ◽  
Amanda B Abrams ◽  
Katharine T Ellis ◽  
Jason C Klein ◽  
Brandon T Ruderman ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Research Effort ◽  
Body Color ◽  
Melanin Production ◽  
Dorsal Portion ◽  
Exon 1 ◽  
Insertion Allele ◽  
Melanin Pathway ◽  
Thomas Hunt Morgan

The pigmentation mutation speck is a commonly used recombination marker characterized by a darkly pigmented region at the wing hinge. Identified in 1910 by Thomas Hunt Morgan, speck was characterized by Sturtevant as the most 'workable' mutant in the rightmost region of the second chromosome and eventually localized to 2-107.0 and 60C1-2. Though the first speck mutation was isolated over 115 years ago, speck is still not associated with any gene. Here, as part of an undergraduate-led research effort, we show that speck is encoded by the Arylalkylamine N-acetyltransferase 1 (AANAT1) gene. Both alleles from the Morgan lab contain a retrotransposon in exon 1 of the RB transcript of the AANAT1 gene. We have also identified a new insertion allele and generated multiple deletion alleles in AANAT1 that all give a strong speck phenotype. In addition, expression of AANAT1 RNAi constructs either ubiquitously or in the dorsal portion of the developing wing generates a similar speck phenotype. We find that speck alleles have additional phenotypes, including ectopic pigmentation in the posterior pupal case, leg joints, cuticular sutures and overall body color. We propose that the acetylated dopamine generated by AANAT1 decreases the dopamine pool available for melanin production. When AANAT1 function is decreased, the excess dopamine enters the melanin pathway to generate the speck phenotype.

scholarly journals “…this Brazilian venture…” A brief biography of Theodosius Dobzhansky before he arrived in Brazil

2020 ◽  
Vol 15 (2) ◽  
pp. 257-289
Author(s):  
William DeJong-Lambert
Keyword(s):  
United States ◽  
Drosophila Melanogaster ◽  
The United States ◽  
Drosophila Pseudoobscura ◽  
Columbia University ◽  
California Institute ◽  
California Institute Of Technology ◽  
Theodosius Dobzhansky ◽  
Institute Of Technology ◽  
Thomas Hunt Morgan

This paper describes life and career of Theodosius Dobzhansky (1900-1975) until he arrived in Brazil in 1943. During his years in Russia, Dobzhansky began his entomology studies and undertook research expeditions to Central Asia to study livestock, which focused on speciation biology. Once he arrived in the United States Dobzhansky began working with Drosophila melanogaster with Thomas Hunt Morgan (1866-1945) at Columbia University. Once Morgan relocated to the California Institute of Technology (Caltech), Dobzhansky started collaborating with his colleague, Alfred Henry Sturtevant (1891-1970), on studies of a wild cousin of Drosophila melanogaster, Drosophila pseudoobscura. Dobzhansky and Sturtevant’s friendship and collaboration suffered due to several factors, including most importantly, their differing approaches to Drosophila pseudoobscura as influenced by their different conceptions of the purpose of their work. While Sturtevant studied the flies using the same techniques as his studies of the domestic Drosophila melanogaster, Dobzhansky studied Drosophila pseudoobscura in the field considering his broader dictum that “Nothing in biology makes sense except in the light of evolution.” 

Identification of a black yeast isolated from oak bark as belonging to the genus Phaeococcomyces sp. Analysis of melanin produced by the yeast

1989 ◽  
Vol 35 (7) ◽  
pp. 728-734 ◽  
Author(s):  
M. J. Butler ◽  
G. Lazarovits ◽  
V. J. Higgins ◽  
M.-A. Lachance
Keyword(s):  
Culture Media ◽  
Average Diameter ◽  
Stationary Growth Phase ◽  
Oxidation Products ◽  
Black Yeast ◽  
Growth Media ◽  
Melanin Production ◽  
Melanin Pigmentation ◽  
Low Levels ◽  
Melanin Pathway

A black fungus isolated from oak bark was identified as a member of the yeast-like genus Phaeococcomyces. While no sexual reproduction was observed, the isolate showed characteristics associated with basidiomycetous yeasts: it was non-fermentative, produced extracellular urease, was positive with the diazonium blue B colony colour test, and had an enteroblastic form of budding. The isolate produced a black pigment constitutively which was shown to be a melanin. Production of the pigment was inhibited by the incorporation of low levels of the fungicide tricyclazole in growth media, inidicating that it was a pentaketide melanin. Pigmentation mutants were produced. Albino mutants did not produce melanin. Diffusion mutants accumulated the pentaketide melanin pathway oxidation products flaviolin and 2-hydroxyjuglone in culture media. Cross-feeder mutants accumulated scytalone, a pentaketide melanin pathway intermediate, in culture media, and caused albino mutants to melanize when grown in proximity to them on agar plates. A single mutant was isolated which excreted 1,8-dihydroxy naphthalene, the end product of the pathway. Broth cultures of Phaeococcomyces sp. in stationary growth phase released melanin in the form of granules, with an average diameter of 30 nm.Key words: black yeast, melanin production, Phaeococcomyces sp.

scholarly journals Structure and transcription of the Drosophila melanogaster vermilion gene and several mutant alleles

1990 ◽  
Vol 10 (4) ◽  
pp. 1423-1431
Author(s):  
L L Searles ◽  
R S Ruth ◽  
A M Pret ◽  
R A Fridell ◽  
A J Ali
Keyword(s):  
Drosophila Melanogaster ◽  
Transcription Initiation ◽  
Donor Site ◽  
Initiation Site ◽  
Splice Donor Site ◽  
Wild Type ◽  
Upstream Site ◽  
Reading Frame ◽  
Exon 1 ◽  
A Minor

The nucleotide sequence and intron-exon structure of the Drosophila melanogaster vermilion (v) gene have been determined. In addition, the sites of several mutations and the effects of these mutations on transcription have been examined. The major v mRNA is generated upon splicing six exons of lengths (5' to 3') 83, 161, 134, 607, 94, and 227 nucleotides (nt). A minor species of v mRNA is initiated at an upstream site and has a 5' exon of at least 152 nt which overlaps the region included in the 83-nt exon of the major v RNA. The three v mutations, v1, v2, and vk, which can be suppressed by mutations at suppressor of sable, su(s), are insertions of transposon 412 at the same position in exon 1, 36 nt downstream of the major transcription initiation site. Despite the 7.5-kilobase insertion in these v alleles, a reduced level of wild-type-sized mRNA accumulates in suppressed mutant strains. The structure and transcription of several unsuppressible v alleles have also been examined. The v36f mutation is a B104/roo insertion in intron 4 near the splice donor site. A mutant carrying this alteration accumulates a very low level of mRNA that is apparently polyadenylated at a site within the B104/roo transposon. The v48a mutation, which deletes approximately 200 nt of DNA, fuses portions of exons 3 and 4 without disruption of the translational reading frame. A smaller transcript accumulates at a wild-type level, and thus an altered, nonfunctional polypeptide is likely to be synthesized in strains carrying this mutation.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals The Drosophila melanogaster actin 5C gene uses two transcription initiation sites and three polyadenylation sites to express multiple mRNA species

1986 ◽  
Vol 6 (6) ◽  
pp. 2080-2088
Author(s):  
B J Bond ◽  
N Davidson
Keyword(s):  
Drosophila Melanogaster ◽  
Transcription Initiation ◽  
Splice Acceptor Site ◽  
Acceptor Site ◽  
Base Pairs ◽  
Exon 2 ◽  
Rna Molecules ◽  
Exon 1 ◽  
Polyadenylation Sites ◽  
Tata Sequence

At least six mRNAs are made from the Drosophila melanogaster act5C gene. We investigated the structures of these RNAs in detail and determined that they are heterogeneous at both their 5' and 3' ends. At the 5' end there were two nonhomologous leader exons which were alternately spliced to the remainder of the gene. These leader exons mapped to 1.7 and 0.7 kilobases, respectively, upstream of a common splice acceptor site which was eight base pairs 5' to the translation initiator AUG. Exon 1 is 147 bases in length, while exon 2 is 111 bases. A consensus TATA sequence was found roughly 30 base pairs upstream from exon 1, but none was found in the analogous position upstream of exon 2. The transcript length diversity arose principally from the use of three polyadenylation sites. This gave rise to RNA molecules with 3'-untranslated regions of roughly 375, 655, and 945 base pairs. With two start sites and three termination sites, this gene has the potential to produce six different transcripts. All six possible transcripts were present in whole fly mRNA. Transcripts containing the two different leader exons were found in roughly the same relative quantities through development. In contrast, the various 3' ends were differentially represented through development.

Genetic analysis of body color phenotypes in the fruit fly Drosophila melanogaster: supporting evidence through laboratory-selected dark and light strains

2012 ◽  
Vol 90 (5) ◽  
pp. 564-576 ◽  
Author(s):  
Ravi Parkash ◽  
Seema Ramniwas ◽  
Babita Kajla
Keyword(s):  
Drosophila Melanogaster ◽  
Phenotypic Plasticity ◽  
Genetic Basis ◽  
Fruit Fly ◽  
Color Variation ◽  
Supporting Evidence ◽  
Body Color ◽  
Wild Populations ◽  
Reciprocal Crosses ◽  
Laboratory Selection

In the fruit fly Drosophila melanogaster Meigen, 1830, abdominal melanisation varies in a quantitative manner, but little attention has been paid to the genetic basis of different phenotypic classes and their ecological significance in the wild populations. Laboratory-selected darker and lighter body color strains were used for determining the genetic basis of body color phenotypes. Based on such genetic characterization, we interpreted body color variation of wild flies collected along a latitudinal gradient. Our results are interesting in several respects. First, laboratory selection produced lighter females and also lighter males, in contradiction of the well-known sexual dimorphism in D. melanogaster. The laboratory-selected darker and lighter strains showed lack of phenotypic plasticity, whereas F1 flies from reciprocal crosses showed significant levels of phenotypic plasticity. Second, for both sexes, F2 phenotypic classes resulting from reciprocal crosses between selected darker and lighter strains fit a two-locus model with a stronger maternal effect in males than in females. Third, changes in continuously varying abdominal melanisation of wild-caught flies were sorted into phenotypic bins of body color phenotypic classes and such data on geographical populations of D. melanogaster are consistent with climatic selection. Thus, we may suggest that for ecological genetic studies, greater emphasis should be laid on the analysis of bins of phenotypic classes of body melanisation in laboratory and wild populations of D. melanogaster.

A developmental and molecular analysis of Cdc2 mutations in Drosophila melanogaster

Genome ◽  
1993 ◽  
Vol 36 (4) ◽  
pp. 676-685 ◽  
Author(s):  
N. J. Clegg ◽  
I. P. Whitehead ◽  
J. A. Williams ◽  
G. B. Spiegelman ◽  
T. A. Grigliatti
Keyword(s):  
Drosophila Melanogaster ◽  
Null Allele ◽  
Donor Site ◽  
Pupal Stage ◽  
P Element ◽  
Splice Donor Site ◽  
Coding Region ◽  
Cdc2 Gene ◽  
Exon 1 ◽  
Single Base Pair

In fission yeast, the product of the cdc2 gene is required both for entry into S phase and mitosis. Homologs of cdc2 have been isolated from a number of metazoans, but in general they have not been amenable to genetic analysis. Here we describe P element transposon tagging of Cdc2 in Drosophila melanogaster and the analysis of 10 Cdc2 mutants. The recessive lethality of Cdc2P is associated with a P element located in the 5′ untranslated region of the gene. Seven other alleles have unique single base pair substitutions in the coding region of Cdc2. One allele, Cdc2B47, is mutated in the splice donor site of exon 1. Most mutations in Cdc2, including the presumptive null allele Cdc2B47, die at the pupal stage, suggesting that the maternally supplied Cdc2 gene product drives earlier cell divisions. The phenotypes of our mutants are consistent with a role for Cdc2 in cell proliferation; however, we did not observe any perturbation of the endoreduplication cycle associated with the acquisition of polyteny.Key words: Cdc2, Drosophila, mutations, sequence.

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