Ivanka Savic, Per Lindström.
Proc. Natl. Acad. Sci. USA, Early Edition | doi:10.1073/pnas.0801566105
Cerebral responses to putative pheromones and objects of sexual attraction were recently found to differ between homo- and heterosexual subjects. Although this observation may merely mirror perceptional differences, it raises the intriguing question as to whether certain sexually dimorphic features in the brain may differ between individuals of the same sex but different sexual orientation. We addressed this issue by studying hemispheric asymmetry and functional connectivity, two parameters that in previous publications have shown specific sex differences. Ninety subjects [25 heterosexual men (HeM) and women (HeW), and 20 homosexual men (HoM) and women (HoW)] were investigated with magnetic resonance volumetry of cerebral and cerebellar hemispheres. Fifty of them also participated in PET measurements of cerebral blood flow, used for analyses of functional connections from the right and left amygdalae. HeM and HoW showed a rightward cerebral asymmetry, whereas volumes of the cerebral hemispheres were symmetrical in HoM and HeW. No cerebellar asymmetries were found. Homosexual subjects also showed sex-atypical amygdala connections. In HoM, as in HeW, the connections were more widespread from the left amygdala; in HoW and HeM, on the other hand, from the right amygdala. Furthermore, in HoM and HeW the connections were primarily displayed with the contralateral amygdala and the anterior cingulate, in HeM and HoW with the caudate, putamen, and the prefrontal cortex. The present study shows sex-atypical cerebral asymmetry and functional connections in homosexual subjects. The results cannot be primarily ascribed to learned effects, and they suggest a linkage to neurobiological entities.# 脳の非対称が男性愛を引き起こすのか、それとも男性愛の結果として脳の非対称が起きたのか？
# 第二次性徴前の子供ではどうなんだろうか？
Björn Reinius, Peter Saetre, Jennifer A. Leonard, Ran Blekhman, Roxana Merino-Martinez, Yoav Gilad, Elena Jazin.
PLoS Genet 4, e1000100 (2008) | doi:10.1371/journal.pgen.1000100
The question of a potential biological sexual signature in the human brain is a heavily disputed subject. In order to provide further insight into this issue, we used an evolutionary approach to identify genes with sex differences in brain expression level among primates. We reasoned that expression patterns important to uphold key male and female characteristics may be conserved during evolution. We selected cortex for our studies because this specific brain region is responsible for many higher behavioral functions. We compared gene expression profiles in the occipital cortex of male and female humans (Homo sapiens, a great ape) and cynomolgus macaques (Macaca fascicularis, an old world monkey), two catarrhine species that show abundant morphological sexual dimorphism, as well as in common marmosets (Callithrix Jacchus, a new world monkey) which are relatively sexually monomorphic. We identified hundreds of genes with sex-biased expression patterns in humans and macaques, while fewer than ten were differentially expressed between the sexes in marmosets. In primates, a general rule is that many of the morphological and behavioral sexual dimorphisms seen in polygamous species, such as macaques, are typically less pronounced in monogamous species such as the marmosets. Our observations suggest that this correlation may also be reflected in the extent of sex-biased gene expression in the brain. We identified 85 genes with common sex-biased expression, in both human and macaque and 2 genes, X inactivation-specific transcript (XIST) and Heat shock factor binding protein 1 (HSBP1), that were consistently sex-biased in the female direction in human, macaque, and marmoset. These observations imply a conserved signature of sexual gene expression dimorphism in cortex of primates. Further, we found that the coding region of female-biased genes is more evolutionarily constrained compared to the coding region of both male-biased and non sex-biased brain expressed genes. We found genes with conserved sexual gene expression dimorphism in the occipital cortex of humans, cynomolgus macaques, and common marmosets. Genes within sexual expression profiles may underlie important functional differences between the sexes, with possible importance during primate evolution.# こっちでは、霊長類では男女の脳で遺伝子発現パターンまで違うなんてことになってます…
# こういうのって継続的にやらないと見つからないんじゃないの？
# 世紀の大発見！…のはずなんだが、盛り上がりに欠けるな…やっぱし液体の水の映像がないとなぁ…
# 水を含む資料の顕微鏡写真に期待
# 「イタリアで開かれた欧州肝臓学会で発表」だそうです
# 「ニタゾキサニドがＣ型肝炎ウイルスに効く理由ははっきりしていない」…要は、何故か知らんが効くらしいってことね
# 「日本基礎老化学会で発表」だそうな
# ミカン果汁のコントロールとして水だけでいいのかとか、カロリー摂取量を合わせたのかとか…
# アスコルビン酸のみの摂取群はないのかとか…ツッコミ甲斐があることは確か…
# 珊瑚の白化をどのくらいの精度で観測出来るんだろう
Danwei Huangfu, René Maehr, Wenjun Guo, Astrid Eijkelenboom, Melinda Snitow, Alice E Chen, Douglas A Melton.
Nature Biotechnology, Advance online publication | doi:10.1038/nbt1418
Reprogramming of mouse and human somatic cells can be achieved by ectopic expression of transcription factors, but with low efficiencies. We report that DNA methyltransferase and histone deacetylase (HDAC) inhibitors improve reprogramming efficiency. In particular, valproic acid (VPA), an HDAC inhibitor, improves reprogramming efficiency by more than 100-fold, using Oct4-GFP as a reporter. VPA also enables efficient induction of pluripotent stem cells without introduction of the oncogene c-Myc.# つまりヒストンの脱アセチル化によってヘテロクロマチン構造をとることで発現が抑制される遺伝子がキーになっているということ？
