規(guī)?；B(yǎng)殖大西洋鱈魚是一些水產(chǎn)專家的夢想，但苦于細菌感染等問題難以成功,。挪威研究人員的一項新發(fā)現(xiàn)可能幫助消除這個障礙,，他們通過基因組測序發(fā)現(xiàn)，大西洋鱈魚的免疫系統(tǒng)非常獨特,。
挪威奧斯陸大學的研究人員最近在英國《自然》雜志網(wǎng)絡版上發(fā)表論文說，大西洋鱈魚缺少一些對脊椎動物非常重要的基因,。
這種現(xiàn)象在有頜類脊椎動物中還是頭一次發(fā)現(xiàn),，將增進人們對脊椎動物免疫系統(tǒng)進化歷程及人類免疫力的理解，還可幫助設計適合大西洋鱈魚的新型疫苗,。
有頜類脊椎動物指有著上,、下頜的脊椎動物，除了一些原始種類,，現(xiàn)存脊椎動物絕大部分都是有頜的,。
研究發(fā)現(xiàn)，大西洋鱈魚的基因組中缺少一組名叫“主要組織相容性復合體Ⅱ”（MHC Ⅱ）的基因,，以及與這組基因有密切關系的另外兩組基因,。這三組基因是多數(shù)脊椎動物后天免疫系統(tǒng)的重要組成部分。
組織中有細菌等病原體侵入時,，MHC Ⅱ基因將病原體的碎片“提交”給免疫細胞,，激發(fā)免疫反應。曾有研究發(fā)現(xiàn),，缺少MHC Ⅱ基因的實驗鼠有免疫缺陷,，會患上嚴重疾病。
與一般脊椎動物相比,，大西洋鱈魚對免疫系統(tǒng)其他一些部分的依賴更重,，這對MHC Ⅱ及相關基因的缺失起到了一定的補償作用，使它們能正常生存,。
研究人員猜測,，大西洋鱈魚可能在有著獨特病原體組合的深水環(huán)境中進化，從而獲得了獨特的免疫系統(tǒng),。(生物谷 Bioon.com)
doi:10.1038/nature10342
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The genome sequence of Atlantic cod reveals a unique immune system
Bastiaan Star; Alexander J. Nederbragt; Sissel Jentoft; Unni Grimholt; Martin Malmstrøm; Tone F. Gregers; Trine B. Rounge; Jonas Paulsen; Monica H. Solbakken; Animesh Sharma; Ola F. Wetten; Anders Lanzén; Roger Winer; James Knight; Jan-Hinnerk Vogel; Bronwen Aken; Øivind Andersen; Karin Lagesen; Ave Tooming-Klunderud; Rolf B. Edvardsen; Kirubakaran G. Tina; Mari Espelund; Chirag Nepal; Christopher Previti; Bård Ove Karlsen; Truls Moum; Morten Skage; Paul R. Berg;
Atlantic cod (Gadus morhua) is a large, cold-adapted teleost that sustains long-standing commercial fisheries and incipient aquaculture1, 2. Here we present the genome sequence of Atlantic cod, showing evidence for complex thermal adaptations in its haemoglobin gene cluster and an unusual immune architecture compared to other sequenced vertebrates. The genome assembly was obtained exclusively by 454 sequencing of shotgun and paired-end libraries, and automated annotation identified 22,154 genes. The major histocompatibility complex (MHC) II is a conserved feature of the adaptive immune system of jawed vertebrates3, 4, but we show that Atlantic cod has lost the genes for MHC II, CD4 and invariant chain (Ii) that are essential for the function of this pathway. Nevertheless, Atlantic cod is not exceptionally susceptible to disease under natural conditions5. We find a highly expanded number of MHC I genes and a unique composition of its Toll-like receptor (TLR) families. This indicates how the Atlantic cod immune system has evolved compensatory mechanisms in both adaptive and innate immunity in the absence of MHC II. These observations affect fundamental assumptions about the evolution of the adaptive immune system and its components in vertebrates.
