據(jù)國(guó)外媒體8月10日?qǐng)?bào)道,，英國(guó)皇家植物園喬德雷爾實(shí)驗(yàn)室的科學(xué)家通過(guò)研究發(fā)現(xiàn)，有些植物對(duì)環(huán)境變化的適應(yīng)速度可能比之前認(rèn)為的要快得多,。這一發(fā)現(xiàn)刊登在近期的《分子生物學(xué)與進(jìn)化》（Molecular Biology and Evolution）上,。
表觀遺傳學(xué)的出現(xiàn)改變了科學(xué)家認(rèn)知這個(gè)世界的方式,，其研究范圍包括對(duì)導(dǎo)致基因功能發(fā)生改變的隱性影響的研究,，而這種影響是在不改變DNA序列的情況下的可遺傳的影響,。按照對(duì)達(dá)爾文進(jìn)化論的現(xiàn)代理解，科學(xué)家原以為只有基因突變才能使得物種出現(xiàn)可遺傳的新特性,，從而適應(yīng)生存環(huán)境的變化，并且這種適應(yīng)會(huì)持續(xù)數(shù)百年,，而讓植物無(wú)法適應(yīng)氣候環(huán)境的快速變化,。
在對(duì)三株不同生長(zhǎng)環(huán)境的新成種蘭花進(jìn)行重點(diǎn)研究時(shí)，科學(xué)家發(fā)現(xiàn),，盡管具有很高的遺傳相似度,，但這三株蘭花在生態(tài)需求,、形態(tài)學(xué)、物理特征和分布上還是表現(xiàn)出了很大的差異,。最終他們得出結(jié)論：表觀遺傳變化會(huì)很大地影響個(gè)體種類的潛在適應(yīng)能力,，而反過(guò)來(lái)，這種適應(yīng)能力會(huì)讓物種的進(jìn)化速度比之前認(rèn)為的要快很多,。這項(xiàng)新發(fā)現(xiàn)意義重大,，它證明了環(huán)境對(duì)基因活動(dòng)的影響是可以被記憶的。
領(lǐng)導(dǎo)該研究的Ovidiu Paun博士表示：“與遺傳信息這個(gè)‘封閉’系統(tǒng)相反的是,，環(huán)境能夠改變個(gè)體種類的表觀遺傳背景,，而個(gè)體通過(guò)這種方式產(chǎn)生適應(yīng)能力也是與現(xiàn)有進(jìn)化觀點(diǎn)的一種互補(bǔ)。研究結(jié)果表明,，達(dá)爾文所說(shuō)的選擇性不只是表現(xiàn)在內(nèi)在基因信息,，同時(shí)也以同樣的方式表現(xiàn)在了表觀遺傳變化，從而使得物種只需經(jīng)過(guò)幾代遺傳,，就能很快地表現(xiàn)出與祖先不同的適應(yīng)性”,。
實(shí)驗(yàn)室負(fù)責(zé)人Mark Chase表示研究結(jié)果“讓我們對(duì)植物的自適應(yīng)能力有了信心”，但他也補(bǔ)充說(shuō),，讓瀕危植物脫離原來(lái)的生存環(huán)境,，移植到像植物園這樣的類似環(huán)境，并不是最佳的保護(hù)策略,，這有可能破壞植物固有的遺傳特性,，最好的辦法還是讓其野外生存。（生物谷Bioon.com）
生物谷推薦原文出處：
Molecular Biology and Evolution, doi:10.1093/molbev/msq150
Stable epigenetic effects impact adaptation in allopolyploid orchids (Dactylorhiza: Orchidaceae)
Ovidiu Paun*,1,2, Richard M. Bateman3, Michael F. Fay1, Mikael Hedrén4, Laure Civeyrel5 and Mark W. Chase1
1 Jodrell Laboratory, Royal Botanic Gardens, Kew, Richmond, Surrey, TW9 3DS, U.K
2 Department of Systematic and Evolutionary Botany, University of Vienna, Rennweg 14, A-1030 Vienna, Austria
3 Department of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, U.K
4 Department of Ecology, Plant Ecology and Systematics, University of Lund, S?lvegatan 37, SE-223 62 Lund, Sweden
5 Laboratoire d'Ecologie Fonctionnelle, UMR 5245, Université de Toulouse, 31062 Toulouse cedex 9, France
Epigenetic information includes heritable signals that modulate gene expression but are not encoded in the primary nucleotide sequence. We have studied natural epigenetic variation in three allotetraploid sibling orchid species (Dactylorhiza majalis s.str, D. traunsteineri s.l. and D. ebudensis) that differ radically in geography/ecology. The epigenetic variation released by genome doubling has been restructured in species-specific patterns that reflect their recent evolutionary history, and have an impact on their ecology and evolution, hundreds of generations after their formation. Using two contrasting approaches that yielded largely congruent results, epigenome scans pinpointed epiloci under divergent selection that correlate with eco-environmental variables, mainly related to water availability and temperature. The stable epigenetic divergence in this group is largely responsible for persistent ecological differences, which then set the stage for species-specific genetic patterns to accumulate in response to further selection and/or drift. Our results strongly suggest a need to expand our current evolutionary framework to encompass a complementary epigenetic dimension when seeking to understand population processes that drive phenotypic evolution and adaptation.
