Determining Whether Drosophila melanogaster Have an Innate Directional Preference Based on the Ambient Magnetic Field of the Earth

The status of the fruit fly Drosophila melanogaster as a model organism for behavioral and genetic research makes it an attractive candidate for investigations of the genetic basis of magnetoreception. There are two main hypotheses for how animals detect Earth-strength magnetic fields. One hypothesis is that animals use magnetite, which forms long chains and serves as a magnetic dipole, while the other hypothesis is that animals have a light-dependent magnetic response utilizing cryptochrome. Several studies have found that Drosophila can orient to Earth-strength magnetic fields using a mechanism consistent with a cryptochrome-based magnetoreceptor, but the specifics of the findings have varied. For example, two studies found that Drosophila have an innate directional preference, while two studies found that Drosophila need to be trained in order to have a directional preference. Additionally, one study found that only male flies orient to magnetic fields, while the other studies found that both male and female flied orient to magnetic fields. To help resolve the conflicting results of these studies, we aimed to determine if Drosophila melanogaster have an innate directional preference and if orientation differs between males and females. We used a sequential Y-maze housed within a Faraday cage, the purpose of which was to block out any radio frequency (RF) fields that mat affect the choices of the flies

Using Artificial Selection to Understand Orientation Behavior in Drosophila

Several studies suggest that the fruit fly Drosophila melanogaster can use magnetic fields for orientation1-4; however, the responses to magnetic fields are not consistent across studies and experiments investigating the mechanism of magnetoreception rely on magnetic fields that are at least 10 times stronger than the magnetic field of the Earth5-6. We are attempting to determine whether Drosophila have the ability to detect Earth-strength magnetic fields by running flies through a progressive Y-maze and then selectively breeding the flies based on their choices in the maze. There are two main hypotheses about the mechanism of magnetoreception in animals. The first is based on the use of magnetite, which forms long chains and serves as a magnetic dipole and has been found in organisms such as bats7. The other hypothesis is based on a light-dependent magnetic response utilizing the cryptochromephotoreceptor8. While the predominant hypothesis is that fruit flies use cryptochrome to detect magnetic fields1-6, experimental results have shown that most invertebrates use magnetite or both magnetite and cryptochrome

A small cohort of FRUM and Engrailed-expressing neurons mediate successful copulation in Drosophila melanogaster

Background: In Drosophila, male flies require the expression of the male-specific Fruitless protein (FRU[superscript M]) within the developing pupal and adult nervous system in order to produce male courtship and copulation behaviors. Recent evidence has shown that specific subsets of FRU[superscript M] neurons are necessary for particular steps of courtship and copulation. In these neurons, FRU[superscript M] function has been shown to be important for determining sex-specific neuronal characteristics, such as neurotransmitter profile and morphology. Results: We identified a small cohort of FRU[superscript M] interneurons in the brain and ventral nerve cord by their co-expression with the transcription factor Engrailed (En). We used an En-GAL4 driver to express a fru[superscript M] RNAi construct in order to selectively deplete FRU[superscript M] in these En/FRU[superscript M] co-expressing neurons. In courtship and copulation tests, these males performed male courtship at wild-type levels but were frequently sterile. Sterility was a behavioral phenotype as these En-fru[superscript M]RNAi males were less able to convert a copulation attempt into a stable copulation, or did not maintain copulation for long enough to transfer sperm and/or seminal fluid. Conclusions: We have identified a population of interneurons necessary for successful copulation in Drosophila. These data confirm a model in which subsets of FRU[superscript M] neurons participate in independent neuronal circuits necessary for individual steps of male behavior. In addition, we have determined that these neurons in wild-type males have homologues in females and fru mutants, with similar placement, projection patterns, and neurochemical profiles

Multisite Evaluation and Validation of a Sensitive Diagnostic and Screening System for Spinal Muscular Atrophy that Reports SMN1 and SMN2 Copy Number, along with Disease Modifier and Gene Duplication Variants

Spinal muscular atrophy is a severe autosomal recessive disease caused by disruptions in the SMN1 gene. The nearly identical SMN2 gene copy number is associated with disease severity. SMN1 duplication markers, such as c.*3+80T>G and c.*211_*212del, can assess residual carrier risk. An SMN2 disease modifier (c.859G>C) can help inform prognostic outcomes. The emergence of multiple precision gene therapies for spinal muscular atrophy requires accurate and rapid detection of SMN1 and SMN2 copy numbers to enable early treatment and optimal patient outcomes. We developed and evaluated a singletube PCR/capillary electrophoresis assay system that quantifies SMN1/2 copy numbers and genotypes three additional clinically relevant variants. Analytical validation was performed with human cell lines and whole blood representing varying SMN1/2 copies on four capillary electrophoresis instrument models. In addition, four independent laboratories used the assay to test 468 residual clinical genomic DNA samples. The results were >98.3% concordant with consensus SMN1/2 exon 7 copy numbers, determined using multiplex ligation-dependent probe amplification and droplet digital PCR, and were 100% concordant with Sanger sequencing for the three variants. Furthermore, copy number values were 98.6% (SMN1) and 97.1% (SMN2) concordant to each laboratory's own reference results. (J Mol Diag

LathamKristinLZoologySmallCohortFRUMfile2.pdf

Background: In Drosophila, male flies require the expression of the male-specific Fruitless protein (FRU[superscript M]) within the developing pupal and adult nervous system in order to produce male courtship and copulation behaviors. Recent evidence has shown that specific subsets of FRU[superscript M] neurons are necessary for particular steps of courtship and copulation. In these neurons, FRU[superscript M] function has been shown to be important for determining sex-specific neuronal characteristics, such as neurotransmitter profile and morphology. Results: We identified a small cohort of FRU[superscript M] interneurons in the brain and ventral nerve cord by their co-expression with the transcription factor Engrailed (En). We used an En-GAL4 driver to express a fru[superscript M] RNAi construct in order to selectively deplete FRU[superscript M] in these En/FRU[superscript M] co-expressing neurons. In courtship and copulation tests, these males performed male courtship at wild-type levels but were frequently sterile. Sterility was a behavioral phenotype as these En-fru[superscript M]RNAi males were less able to convert a copulation attempt into a stable copulation, or did not maintain copulation for long enough to transfer sperm and/or seminal fluid. Conclusions: We have identified a population of interneurons necessary for successful copulation in Drosophila. These data confirm a model in which subsets of FRU[superscript M] neurons participate in independent neuronal circuits necessary for individual steps of male behavior. In addition, we have determined that these neurons in wild-type males have homologues in females and fru mutants, with similar placement, projection patterns, and neurochemical profiles

LathamKristinLZoologySmallCohortFRUM.pdf

Background: In Drosophila, male flies require the expression of the male-specific Fruitless protein (FRU[superscript M]) within the developing pupal and adult nervous system in order to produce male courtship and copulation behaviors. Recent evidence has shown that specific subsets of FRU[superscript M] neurons are necessary for particular steps of courtship and copulation. In these neurons, FRU[superscript M] function has been shown to be important for determining sex-specific neuronal characteristics, such as neurotransmitter profile and morphology. Results: We identified a small cohort of FRU[superscript M] interneurons in the brain and ventral nerve cord by their co-expression with the transcription factor Engrailed (En). We used an En-GAL4 driver to express a fru[superscript M] RNAi construct in order to selectively deplete FRU[superscript M] in these En/FRU[superscript M] co-expressing neurons. In courtship and copulation tests, these males performed male courtship at wild-type levels but were frequently sterile. Sterility was a behavioral phenotype as these En-fru[superscript M]RNAi males were less able to convert a copulation attempt into a stable copulation, or did not maintain copulation for long enough to transfer sperm and/or seminal fluid. Conclusions: We have identified a population of interneurons necessary for successful copulation in Drosophila. These data confirm a model in which subsets of FRU[superscript M] neurons participate in independent neuronal circuits necessary for individual steps of male behavior. In addition, we have determined that these neurons in wild-type males have homologues in females and fru mutants, with similar placement, projection patterns, and neurochemical profiles

LathamKristinLZoologySmallCohortFRUMfile3.pdf

Background: In Drosophila, male flies require the expression of the male-specific Fruitless protein (FRU[superscript M]) within the developing pupal and adult nervous system in order to produce male courtship and copulation behaviors. Recent evidence has shown that specific subsets of FRU[superscript M] neurons are necessary for particular steps of courtship and copulation. In these neurons, FRU[superscript M] function has been shown to be important for determining sex-specific neuronal characteristics, such as neurotransmitter profile and morphology. Results: We identified a small cohort of FRU[superscript M] interneurons in the brain and ventral nerve cord by their co-expression with the transcription factor Engrailed (En). We used an En-GAL4 driver to express a fru[superscript M] RNAi construct in order to selectively deplete FRU[superscript M] in these En/FRU[superscript M] co-expressing neurons. In courtship and copulation tests, these males performed male courtship at wild-type levels but were frequently sterile. Sterility was a behavioral phenotype as these En-fru[superscript M]RNAi males were less able to convert a copulation attempt into a stable copulation, or did not maintain copulation for long enough to transfer sperm and/or seminal fluid. Conclusions: We have identified a population of interneurons necessary for successful copulation in Drosophila. These data confirm a model in which subsets of FRU[superscript M] neurons participate in independent neuronal circuits necessary for individual steps of male behavior. In addition, we have determined that these neurons in wild-type males have homologues in females and fru mutants, with similar placement, projection patterns, and neurochemical profiles

LathamKristinLZoologySmallCohortFRUMfile4.pdf

Background: In Drosophila, male flies require the expression of the male-specific Fruitless protein (FRU[superscript M]) within the developing pupal and adult nervous system in order to produce male courtship and copulation behaviors. Recent evidence has shown that specific subsets of FRU[superscript M] neurons are necessary for particular steps of courtship and copulation. In these neurons, FRU[superscript M] function has been shown to be important for determining sex-specific neuronal characteristics, such as neurotransmitter profile and morphology. Results: We identified a small cohort of FRU[superscript M] interneurons in the brain and ventral nerve cord by their co-expression with the transcription factor Engrailed (En). We used an En-GAL4 driver to express a fru[superscript M] RNAi construct in order to selectively deplete FRU[superscript M] in these En/FRU[superscript M] co-expressing neurons. In courtship and copulation tests, these males performed male courtship at wild-type levels but were frequently sterile. Sterility was a behavioral phenotype as these En-fru[superscript M]RNAi males were less able to convert a copulation attempt into a stable copulation, or did not maintain copulation for long enough to transfer sperm and/or seminal fluid. Conclusions: We have identified a population of interneurons necessary for successful copulation in Drosophila. These data confirm a model in which subsets of FRU[superscript M] neurons participate in independent neuronal circuits necessary for individual steps of male behavior. In addition, we have determined that these neurons in wild-type males have homologues in females and fru mutants, with similar placement, projection patterns, and neurochemical profiles

LathamKristinLZoologySmallCohortFRUMfile1.pdf

Background: In Drosophila, male flies require the expression of the male-specific Fruitless protein (FRU[superscript M]) within the developing pupal and adult nervous system in order to produce male courtship and copulation behaviors. Recent evidence has shown that specific subsets of FRU[superscript M] neurons are necessary for particular steps of courtship and copulation. In these neurons, FRU[superscript M] function has been shown to be important for determining sex-specific neuronal characteristics, such as neurotransmitter profile and morphology. Results: We identified a small cohort of FRU[superscript M] interneurons in the brain and ventral nerve cord by their co-expression with the transcription factor Engrailed (En). We used an En-GAL4 driver to express a fru[superscript M] RNAi construct in order to selectively deplete FRU[superscript M] in these En/FRU[superscript M] co-expressing neurons. In courtship and copulation tests, these males performed male courtship at wild-type levels but were frequently sterile. Sterility was a behavioral phenotype as these En-fru[superscript M]RNAi males were less able to convert a copulation attempt into a stable copulation, or did not maintain copulation for long enough to transfer sperm and/or seminal fluid. Conclusions: We have identified a population of interneurons necessary for successful copulation in Drosophila. These data confirm a model in which subsets of FRU[superscript M] neurons participate in independent neuronal circuits necessary for individual steps of male behavior. In addition, we have determined that these neurons in wild-type males have homologues in females and fru mutants, with similar placement, projection patterns, and neurochemical profiles