同源染色體基因表達活性不同的現(xiàn)象,，稱為基因印記。據(jù)美國物理學(xué)家組織網(wǎng)報道,，英國巴斯大學(xué)科學(xué)家近日發(fā)現(xiàn)了一種名為Grb10的基因，與通常的印記基因表達規(guī)則不符的是，它從父母雙方遺傳下來的等位基因作用截然不同,。相關(guān)研究發(fā)表在近期出版的《自然》雜志上。
所有動物的細胞中,，每個基因組都是成對出現(xiàn)：一條來自父親,，另一條來自母親。多數(shù)情況下這兩條基因都是活躍的,，但對某些基因而言,，其中一條被關(guān)閉了，基因僅能表達來自一方的同源基因,，而另一方的不表達,。
巴斯大學(xué)研究人員與加地夫大學(xué)神經(jīng)系統(tǒng)科學(xué)與精神健康研究院科學(xué)家合作，發(fā)現(xiàn)了一種名為Grb10的基因,，其異常之處在于,，子代只在大腦中表達來自父方的基因,，卻在身體其他部位表達來自母方的基因——好像父母雙方的印記基因各自在不同部位有一種無意識的優(yōu)先權(quán)：母親的基因表達涉及胎兒成長、新陳代謝,、脂肪儲存,，而父親的基因表達調(diào)控著成人的社會行為。
為了證實這一點,，他們對缺乏父方Grb10基因的小鼠進行了行為研究,。在一項強制遭遇測試中，研究人員將兩組小鼠放置在一條狹窄管道的兩端,，并阻止它們轉(zhuǎn)身,，結(jié)果發(fā)現(xiàn)，Grb10基因在大腦中不活躍的小鼠通常會堅守原地,，而其它小鼠則會倒退,，并表現(xiàn)順從。缺乏父方Grb10基因的小鼠更喜歡控制其它小鼠,，與腦中父方Grb10基因活躍的小鼠相比,，更有可能獲得同伴禮貌的待遇，這在小鼠和其它哺乳動物中是一種處于統(tǒng)治地位的標志,。此外,，這些小鼠還更有可能扯斷同籠的表達等位基因小鼠的胡須。當母方Grb10等位基因表達沉默時,，小鼠通常會變得又大又重,。
巴斯大學(xué)再生醫(yī)學(xué)研究中心的安德魯·沃德說：“這是首次，我們證明了同一個基因根據(jù)其來自父母雙方的不同,，可以有完全不同的功能,。好像是父母雙方以不同的策略來幫助后代，一方致力于身體,，而另一方致力于精神,。”
研究證明，印記基因?qū)θ祟惤】捣浅Ｖ匾?。Grb10與胚胎發(fā)育有關(guān),，而在后期生命中，它對身體和精神兩方面都很重要,。“一種基因能影響大腦和肌肉兩方面是令人吃驚的,。今后我們將研究Grb10基因如何進化出這種雙重功能。”（生物谷Bioon.com）
生物谷推薦原文出處：
Nature doi:10.1038/nature09651
Distinct physiological and behavioural functions for parental alleles of imprinted Grb10
Alastair S. Garfield,Michael Cowley,Florentia M. Smith,Kim Moorwood,Joanne E. Stewart-Cox,Kerry Gilroy,Sian Baker,Jing Xia,Jeffrey W. Dalley,Laurence D. Hurst,Lawrence S. Wilkinson,Anthony R. Isles& Andrew Ward
Imprinted genes, defined by their preferential expression of a single parental allele, represent a subset of the mammalian genome and often have key roles in embryonic development1, but also postnatal functions including energy homeostasis2 and behaviour3, 4. When the two parental alleles are unequally represented within a social group (when there is sex bias in dispersal and/or variance in reproductive success)5, 6, imprinted genes may evolve to modulate social behaviour, although so far no such instance is known. Predominantly expressed from the maternal allele during embryogenesis, Grb10 encodes an intracellular adaptor protein that can interact with several receptor tyrosine kinases and downstream signalling molecules7. Here we demonstrate that within the brain Grb10 is expressed from the paternal allele from fetal life into adulthood and that ablation of this expression engenders increased social dominance specifically among other aspects of social behaviour, a finding supported by the observed increase in allogrooming by paternal Grb10-deficient animals. Grb10 is, therefore, the first example of an imprinted gene that regulates social behaviour. It is also currently alone in exhibiting imprinted expression from each of the parental alleles in a tissue-specific manner, as loss of the peripherally expressed maternal allele leads to significant fetal and placental overgrowth. Thus Grb10 is, so far, a unique imprinted gene, able to influence distinct physiological processes, fetal growth and adult behaviour, owing to actions of the two parental alleles in different tissues.
