<i>speck</i>, First Identified in <i>Drosophila melanogaster</i> in 1910, Is Encoded by the Arylalkalamine N-Acetyltransferase (AANAT1) Gene.


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.





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Publication Info

Spana, Eric P, Amanda B Abrams, Katharine T Ellis, Jason C Klein, Brandon T Ruderman, Alvin H Shi, Daniel Zhu, Andrea Stewart, et al. (2020). speck, First Identified in Drosophila melanogaster in 1910, Is Encoded by the Arylalkalamine N-Acetyltransferase (AANAT1) Gene. G3 (Bethesda, Md.), 10(9). pp. 3387–3398. 10.1534/g3.120.401470 Retrieved from https://hdl.handle.net/10161/25640.

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Eric P. Spana

Associate Professor of the Practice of Biology

Brandon T Ruderman

Assistant Professor of Emergency Medicine

Brandon Ruderman, MD, FACEP is an Assistant Professor in the Department of Emergency Medicine at Duke University School of Medicine. He graduated cum laude with distinction from Duke University with a Bachelor's of Science in Biology and a Certificate in Genome Sciences and Policy. He received his medical degree from the University of Rochester School of Medicine and Dentistry, where he also received the Marvin J. Hoffman International Medicine Award for a research project in Peru as well as the Society for Academic Emergency Medicine Medical Student Excellence in Emergency Medicine Award. He completed his residency training in Emergency Medicine at Duke University Medical Center, followed by a fellowship in Emergency Ultrasound at Duke. 

Dr. Ruderman joined Duke Emergency Medicine Faculty in 2020 after his fellowship, and his primary interests include medical student and resident ultrasound education, simulation, exploring novel applications of point-of-care ultrasound, and emergency airway research. He was a finalist in the 2018 American College of Emergency Physicians Research Forum Best Resident Abstract for his research comparing video laryngoscopy to direct laryngoscopy in patients with difficult airways. He has served in numerous roles as one of the Duke Emergency Ultrasound Faculty, including mentoring several medical students and residents, and as the Ultrasound Course Director for the Acute Care course for fourth year students at Duke University School of Medicine.

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