據(jù)3月14日PLoS ONE上發(fā)表的文章報(bào)道,,日本研究人員研究證實(shí)被長期飼養(yǎng)在黑暗環(huán)境中的果蠅,,促進(jìn)解毒的基因會出現(xiàn)變異。他們認(rèn)為,,果蠅有可能通過增強(qiáng)對毒性的抵抗力,,更加適應(yīng)在黑暗環(huán)境中生活。
果蠅本是一種晝行性昆蟲,,為了調(diào)查生物對環(huán)境的適應(yīng)能力,,京都大學(xué)從1954年開始,一直在黑暗環(huán)境中飼養(yǎng)果蠅,,已培育了約1400代,。在本項(xiàng)研究中,京大研究員布施直之率領(lǐng)的研究小組解讀了20只雄性果蠅的基因組,,然后與普通果蠅進(jìn)行比較,。他們發(fā)現(xiàn)在約1.4萬個基因中,有241個出現(xiàn)了變異并被遺傳下來,。而在出現(xiàn)變異的基因中,,有很多負(fù)責(zé)合成酶以排出進(jìn)入果蠅體內(nèi)的毒素。研究小組認(rèn)為雌性果蠅體內(nèi)存在同樣的變異,。
此外,,研究人員在調(diào)查果蠅壽命時,,發(fā)現(xiàn)普通的雌性果蠅在產(chǎn)卵后或突然被放到黑暗處飼養(yǎng)壽命會縮短,但是長期在黑暗中生活的果蠅,,產(chǎn)卵后也能存活很長時間,。布施直之指出:“對黑暗環(huán)境和毒性的耐受性可能與壽命有關(guān)。”
研究小組準(zhǔn)備進(jìn)一步調(diào)查基因變異的影響,,弄清變異的機(jī)制,。日本國立遺傳學(xué)研究所和美國哈佛大學(xué)的研究人員也參與了這項(xiàng)研究。(生物谷 bioon.com)
doi:10.1371/journal.pone.0033288
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Genome Features of “Dark-Fly”, a Drosophila Line Reared Long-Term in a Dark Environment
Minako Izutsu1, Jun Zhou, Yuzo Sugiyama, Osamu Nishimura, Tomoyuki Aizu, Atsushi Toyoda, Asao Fujiyama, Kiyokazu Agata, Naoyuki Fuse
Organisms are remarkably adapted to diverse environments by specialized metabolisms, morphology, or behaviors. To address the molecular mechanisms underlying environmental adaptation, we have utilized a Drosophila melanogaster line, termed “Dark-fly”, which has been maintained in constant dark conditions for 57 years (1400 generations). We found that Dark-fly exhibited higher fecundity in dark than in light conditions, indicating that Dark-fly possesses some traits advantageous in darkness. Using next-generation sequencing technology, we determined the whole genome sequence of Dark-fly and identified approximately 220,000 single nucleotide polymorphisms (SNPs) and 4,700 insertions or deletions (InDels) in the Dark-fly genome compared to the genome of the Oregon-R-S strain, a control strain. 1.8% of SNPs were classified as non-synonymous SNPs (nsSNPs: i.e., they alter the amino acid sequence of gene products). Among them, we detected 28 nonsense mutations (i.e., they produce a stop codon in the protein sequence) in the Dark-fly genome. These included genes encoding an olfactory receptor and a light receptor. We also searched runs of homozygosity (ROH) regions as putative regions selected during the population history, and found 21 ROH regions in the Dark-fly genome. We identified 241 genes carrying nsSNPs or InDels in the ROH regions. These include a cluster of alpha-esterase genes that are involved in detoxification processes. Furthermore, analysis of structural variants in the Dark-fly genome showed the deletion of a gene related to fatty acid metabolism. Our results revealed unique features of the Dark-fly genome and provided a list of potential candidate genes involved in environmental adaptation.