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Sexual dimorphism in the fly brain.

Cachero S, Ostrovsky AD, Yu JY, Dickson BJ, Jefferis GS - Curr. Biol. (2010)

Bottom Line: Initial work found limited evidence for anatomical dimorphism in these fru+ neurons.Our analysis reveals substantial differences in wiring and gross anatomy between male and female fly brains.Reciprocal connection differences in the lateral horn offer a plausible explanation for opposing responses to sex pheromones in male and female flies.

View Article: PubMed Central - PubMed

Affiliation: Division of Neurobiology, MRC Laboratory of Molecular Biology, Cambridge, UK.

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Male-Enlarged Regions Are Genotype Specific and Colocalize with fruitless Expression(A) Schematic of Drosophila neuropil compartments and olfactory system. Projection neurons are cyan, mushroom body neurons are green.(B) Surface rendering of male (green)- and female (magenta)-enlarged regions on our template brain.(C) Summary of main male-enlarged regions (MERs). Green: pars intercerebralis; red: arch; mustard: ring; turquoise: lateral junction; light blue: DA1 glomerulus; yellow: tips of mushroom body gamma lobes.(D–K) Two individual slices from average template brains for control male (D and H), control female (E and I), tra mutant female (F and J), and fruM mutant female (G and K). In (D)–(G), arrow indicates male-enlarged arch; in (H)–(K), it shows the male expansion of the ring neuropil.(L) Overlap between MERs (blue) and fruGal4 expression pattern (green).(M and N) Z projections (standard deviation) of the fruGal4 driving CD8-GFP in males (M) and females (N). For clarity, cell bodies in the surface of the brain and the mushroom bodies have been removed. A false color lookup table has been applied to emphasize contrast.(O) Schematic of Drosophila sex determination hierarchy. Bold-type gene products are active, gray are inactive.(P) Quantification of the volume of the MER for control and mutant flies. The central line indicates the median, the box represents the 25% and 75% quartiles, and the whiskers extend to ±1.5 times the interquartile range.Scale bar in all panels represents 50 μm. See also Figure S1.
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fig1: Male-Enlarged Regions Are Genotype Specific and Colocalize with fruitless Expression(A) Schematic of Drosophila neuropil compartments and olfactory system. Projection neurons are cyan, mushroom body neurons are green.(B) Surface rendering of male (green)- and female (magenta)-enlarged regions on our template brain.(C) Summary of main male-enlarged regions (MERs). Green: pars intercerebralis; red: arch; mustard: ring; turquoise: lateral junction; light blue: DA1 glomerulus; yellow: tips of mushroom body gamma lobes.(D–K) Two individual slices from average template brains for control male (D and H), control female (E and I), tra mutant female (F and J), and fruM mutant female (G and K). In (D)–(G), arrow indicates male-enlarged arch; in (H)–(K), it shows the male expansion of the ring neuropil.(L) Overlap between MERs (blue) and fruGal4 expression pattern (green).(M and N) Z projections (standard deviation) of the fruGal4 driving CD8-GFP in males (M) and females (N). For clarity, cell bodies in the surface of the brain and the mushroom bodies have been removed. A false color lookup table has been applied to emphasize contrast.(O) Schematic of Drosophila sex determination hierarchy. Bold-type gene products are active, gray are inactive.(P) Quantification of the volume of the MER for control and mutant flies. The central line indicates the median, the box represents the 25% and 75% quartiles, and the whiskers extend to ±1.5 times the interquartile range.Scale bar in all panels represents 50 μm. See also Figure S1.

Mentions: The fruit fly Drosophila melanogaster displays robust, highly stereotyped and dimorphic sexual behaviors [1] that provide an ideal model system to study the genetic and neural basis of innate behavior. The genetic pathways that translate chromosomal sex into dimorphic behavior have been studied extensively [2, 3] (Figure 1O). Early studies using sex mosaics mapped different steps of male courtship to broad regions of the central nervous system [4, 5]. Such results suggest that there are anatomical and functional differences between the sexes in these brain regions. At the level of gross anatomy, few structural dimorphisms have been found, and most are small [6, 7]. However, three olfactory glomeruli show volume differences of 25%–60% [8, 9], and two of these have been linked to sex-specific odor processing.


Sexual dimorphism in the fly brain.

Cachero S, Ostrovsky AD, Yu JY, Dickson BJ, Jefferis GS - Curr. Biol. (2010)

Male-Enlarged Regions Are Genotype Specific and Colocalize with fruitless Expression(A) Schematic of Drosophila neuropil compartments and olfactory system. Projection neurons are cyan, mushroom body neurons are green.(B) Surface rendering of male (green)- and female (magenta)-enlarged regions on our template brain.(C) Summary of main male-enlarged regions (MERs). Green: pars intercerebralis; red: arch; mustard: ring; turquoise: lateral junction; light blue: DA1 glomerulus; yellow: tips of mushroom body gamma lobes.(D–K) Two individual slices from average template brains for control male (D and H), control female (E and I), tra mutant female (F and J), and fruM mutant female (G and K). In (D)–(G), arrow indicates male-enlarged arch; in (H)–(K), it shows the male expansion of the ring neuropil.(L) Overlap between MERs (blue) and fruGal4 expression pattern (green).(M and N) Z projections (standard deviation) of the fruGal4 driving CD8-GFP in males (M) and females (N). For clarity, cell bodies in the surface of the brain and the mushroom bodies have been removed. A false color lookup table has been applied to emphasize contrast.(O) Schematic of Drosophila sex determination hierarchy. Bold-type gene products are active, gray are inactive.(P) Quantification of the volume of the MER for control and mutant flies. The central line indicates the median, the box represents the 25% and 75% quartiles, and the whiskers extend to ±1.5 times the interquartile range.Scale bar in all panels represents 50 μm. See also Figure S1.
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fig1: Male-Enlarged Regions Are Genotype Specific and Colocalize with fruitless Expression(A) Schematic of Drosophila neuropil compartments and olfactory system. Projection neurons are cyan, mushroom body neurons are green.(B) Surface rendering of male (green)- and female (magenta)-enlarged regions on our template brain.(C) Summary of main male-enlarged regions (MERs). Green: pars intercerebralis; red: arch; mustard: ring; turquoise: lateral junction; light blue: DA1 glomerulus; yellow: tips of mushroom body gamma lobes.(D–K) Two individual slices from average template brains for control male (D and H), control female (E and I), tra mutant female (F and J), and fruM mutant female (G and K). In (D)–(G), arrow indicates male-enlarged arch; in (H)–(K), it shows the male expansion of the ring neuropil.(L) Overlap between MERs (blue) and fruGal4 expression pattern (green).(M and N) Z projections (standard deviation) of the fruGal4 driving CD8-GFP in males (M) and females (N). For clarity, cell bodies in the surface of the brain and the mushroom bodies have been removed. A false color lookup table has been applied to emphasize contrast.(O) Schematic of Drosophila sex determination hierarchy. Bold-type gene products are active, gray are inactive.(P) Quantification of the volume of the MER for control and mutant flies. The central line indicates the median, the box represents the 25% and 75% quartiles, and the whiskers extend to ±1.5 times the interquartile range.Scale bar in all panels represents 50 μm. See also Figure S1.
Mentions: The fruit fly Drosophila melanogaster displays robust, highly stereotyped and dimorphic sexual behaviors [1] that provide an ideal model system to study the genetic and neural basis of innate behavior. The genetic pathways that translate chromosomal sex into dimorphic behavior have been studied extensively [2, 3] (Figure 1O). Early studies using sex mosaics mapped different steps of male courtship to broad regions of the central nervous system [4, 5]. Such results suggest that there are anatomical and functional differences between the sexes in these brain regions. At the level of gross anatomy, few structural dimorphisms have been found, and most are small [6, 7]. However, three olfactory glomeruli show volume differences of 25%–60% [8, 9], and two of these have been linked to sex-specific odor processing.

Bottom Line: Initial work found limited evidence for anatomical dimorphism in these fru+ neurons.Our analysis reveals substantial differences in wiring and gross anatomy between male and female fly brains.Reciprocal connection differences in the lateral horn offer a plausible explanation for opposing responses to sex pheromones in male and female flies.

View Article: PubMed Central - PubMed

Affiliation: Division of Neurobiology, MRC Laboratory of Molecular Biology, Cambridge, UK.

Show MeSH
Related in: MedlinePlus