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Sexual differentiation of the zebra finch song system: potential roles for sex chromosome genes.

Tomaszycki ML, Peabody C, Replogle K, Clayton DF, Tempelman RJ, Wade J - BMC Neurosci (2009)

Bottom Line: Recent evidence suggests that some sex differences in brain and behavior might result from direct genetic effects, and not solely the result of the organizational effects of steroid hormones.The present study examined the potential role for sex-biased gene expression during development of sexually dimorphic singing behavior and associated song nuclei in juvenile zebra finches.Although the function of half of the genes is presently unknown, we have identified three as: 17-beta-hydroxysteroid dehydrogenase type IV, methylcrotonyl-CoA carboxylase, and sorting nexin 2.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Psychology & Program in Neuroscience, Michigan State University, East Lansing, MI, USA. tomaszy1@msu.edu

ABSTRACT

Background: Recent evidence suggests that some sex differences in brain and behavior might result from direct genetic effects, and not solely the result of the organizational effects of steroid hormones. The present study examined the potential role for sex-biased gene expression during development of sexually dimorphic singing behavior and associated song nuclei in juvenile zebra finches.

Results: A microarray screen revealed more than 2400 putative genes (with a false discovery rate less than 0.05) exhibiting sex differences in the telencephalon of developing zebra finches. Increased expression in males was confirmed in 12 of 20 by qPCR using cDNA from the whole telencephalon; all of these appeared to be located on the Z sex chromosome. Six of the genes also showed increased expression in one or more of the song control nuclei of males at post-hatching day 25. Although the function of half of the genes is presently unknown, we have identified three as: 17-beta-hydroxysteroid dehydrogenase type IV, methylcrotonyl-CoA carboxylase, and sorting nexin 2.

Conclusion: The data suggest potential influences of these genes in song learning and/or masculinization of song system morphology, both of which are occurring at this developmental stage.

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Related in: MedlinePlus

Darkfield images from in situ hybridization depicting sexually dimorphic mRNA expression for CK306803(Sorting nexin 2) in the zebra finch song system at day 25 post-hatching. Arrows delineate borders of song regions. In area X (or the portion of the medial striatum containing it), males (A) showed higher levels of mRNA expression than did females (B). The increased expression of this gene in males (C) compared to females (D) was also detected in HVC. Scale bar = 200 μm for area X and 100 μm for HVC.
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Figure 4: Darkfield images from in situ hybridization depicting sexually dimorphic mRNA expression for CK306803(Sorting nexin 2) in the zebra finch song system at day 25 post-hatching. Arrows delineate borders of song regions. In area X (or the portion of the medial striatum containing it), males (A) showed higher levels of mRNA expression than did females (B). The increased expression of this gene in males (C) compared to females (D) was also detected in HVC. Scale bar = 200 μm for area X and 100 μm for HVC.

Mentions: Three of the four song nuclei (lMAN, Area X, and HVC) exhibited specific labeling indicating SNX 2 mRNA [GenBank: CK306803]. It was increased in males in area X and HVC (t = 2.85, p = 0.017; t = 11.10, p < 0.001, respectively; Figure 4). Expression between the sexes, however, did not differ in lMAN (t = 0.94, p = 0.370).


Sexual differentiation of the zebra finch song system: potential roles for sex chromosome genes.

Tomaszycki ML, Peabody C, Replogle K, Clayton DF, Tempelman RJ, Wade J - BMC Neurosci (2009)

Darkfield images from in situ hybridization depicting sexually dimorphic mRNA expression for CK306803(Sorting nexin 2) in the zebra finch song system at day 25 post-hatching. Arrows delineate borders of song regions. In area X (or the portion of the medial striatum containing it), males (A) showed higher levels of mRNA expression than did females (B). The increased expression of this gene in males (C) compared to females (D) was also detected in HVC. Scale bar = 200 μm for area X and 100 μm for HVC.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2664819&req=5

Figure 4: Darkfield images from in situ hybridization depicting sexually dimorphic mRNA expression for CK306803(Sorting nexin 2) in the zebra finch song system at day 25 post-hatching. Arrows delineate borders of song regions. In area X (or the portion of the medial striatum containing it), males (A) showed higher levels of mRNA expression than did females (B). The increased expression of this gene in males (C) compared to females (D) was also detected in HVC. Scale bar = 200 μm for area X and 100 μm for HVC.
Mentions: Three of the four song nuclei (lMAN, Area X, and HVC) exhibited specific labeling indicating SNX 2 mRNA [GenBank: CK306803]. It was increased in males in area X and HVC (t = 2.85, p = 0.017; t = 11.10, p < 0.001, respectively; Figure 4). Expression between the sexes, however, did not differ in lMAN (t = 0.94, p = 0.370).

Bottom Line: Recent evidence suggests that some sex differences in brain and behavior might result from direct genetic effects, and not solely the result of the organizational effects of steroid hormones.The present study examined the potential role for sex-biased gene expression during development of sexually dimorphic singing behavior and associated song nuclei in juvenile zebra finches.Although the function of half of the genes is presently unknown, we have identified three as: 17-beta-hydroxysteroid dehydrogenase type IV, methylcrotonyl-CoA carboxylase, and sorting nexin 2.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Psychology & Program in Neuroscience, Michigan State University, East Lansing, MI, USA. tomaszy1@msu.edu

ABSTRACT

Background: Recent evidence suggests that some sex differences in brain and behavior might result from direct genetic effects, and not solely the result of the organizational effects of steroid hormones. The present study examined the potential role for sex-biased gene expression during development of sexually dimorphic singing behavior and associated song nuclei in juvenile zebra finches.

Results: A microarray screen revealed more than 2400 putative genes (with a false discovery rate less than 0.05) exhibiting sex differences in the telencephalon of developing zebra finches. Increased expression in males was confirmed in 12 of 20 by qPCR using cDNA from the whole telencephalon; all of these appeared to be located on the Z sex chromosome. Six of the genes also showed increased expression in one or more of the song control nuclei of males at post-hatching day 25. Although the function of half of the genes is presently unknown, we have identified three as: 17-beta-hydroxysteroid dehydrogenase type IV, methylcrotonyl-CoA carboxylase, and sorting nexin 2.

Conclusion: The data suggest potential influences of these genes in song learning and/or masculinization of song system morphology, both of which are occurring at this developmental stage.

Show MeSH
Related in: MedlinePlus