Nature發(fā)表了黑青斑河豚（Tetraodon nigroviridis）的基因組序列草圖,。黑青斑河豚和相關(guān)的紅鰭多紀(jì)（Takifugu rubripes）作為研究工具對(duì)演化遺傳學(xué)家來說有很多優(yōu)勢(shì),，更不用說它們是已知最小的脊椎動(dòng)物基因組了。
被認(rèn)為魚類所沒有的關(guān)鍵基因現(xiàn)在已在黑青斑河豚身上識(shí)別出來,，與人類基因組所做的比較顯示出900個(gè)以前沒有標(biāo)記的基因,。在其與哺乳動(dòng)物分化之后的某個(gè)時(shí)候，在硬骨魚類中發(fā)生了整基因組復(fù)制,。
與人類和小鼠基因組所做的比較顯示出最早有骨基因組（在哺乳動(dòng)物出現(xiàn)前已知最近的有骨魚）的基本結(jié)構(gòu),，這是一個(gè)緊湊型基因組，只有12個(gè)染色體。
河豚是一種顏色鮮艷的魚類,。新近公布的河豚基因組圖譜表明有骨魚和人類的共有的脊椎動(dòng)物祖先只有12對(duì)染色體,，但后來魚類在與人類分化開后將基因組擴(kuò)增了一倍。研究人員將這些結(jié)果發(fā)表在10月20日的Nature上,。
綠點(diǎn)的黑青斑河豚（Tetraodon nigroviridis）是大約20000種有魚鰭魚類中的一種,。大約在4500萬年前，鰭魚的祖先與其它脊椎動(dòng)物如青蛙,、小雞和人類等家族分化開來,。對(duì)其它鰭魚的基因的研究表明在鰭魚進(jìn)化的過程中，整個(gè)基因組發(fā)生了復(fù)制（1998年11月27日Science,，1711頁）,。但是由于缺乏證據(jù)，人們對(duì)這種觀點(diǎn)存在爭(zhēng)議,。
現(xiàn)在,，麻省理工和哈佛大學(xué)的研究人員已經(jīng)完成了這種河豚基因組（脊椎動(dòng)物中最小的基因組）的測(cè)序工作，并且找出了具有數(shù)百個(gè)重復(fù)的基因的染色體區(qū)域,。當(dāng)研究人員將超過6000個(gè)河豚基因的位置與人類基因組中相應(yīng)的基因的位置進(jìn)行比較時(shí)發(fā)現(xiàn),，人類染色體中的一個(gè)染色體區(qū)域與河豚基因組中的兩個(gè)區(qū)域相符合。這意味著人類和河豚的共同祖先只有12條染色體,，并且在鰭魚進(jìn)化過程中整個(gè)基因組被復(fù)制,。
河豚基因組較小表明在基因組被復(fù)制后又發(fā)生了大量的刪減。這些分析結(jié)果讓研究人員對(duì)基因組進(jìn)化的過去和將來有了一定的了解,。
Tetraodon nigroviridis is a freshwater puffer fish with the smallest known vertebrate genome. Here, we report a draft genome sequence with long-range linkage and substantial anchoring to the 21 Tetraodon chromosomes. Genome analysis provides a greatly improved fish gene catalogue, including identifying key genes previously thought to be absent in fish. Comparison with other vertebrates and a urochordate indicates that fish proteins have diverged markedly faster than their mammalian homologues. Comparison with the human genome suggests 900 previously unannotated human genes. Analysis of the Tetraodon and human genomes shows that whole-genome duplication occurred in the teleost fish lineage, subsequent to its divergence from mammals. The analysis also makes it possible to infer the basic structure of the ancestral bony vertebrate genome, which was composed of 12 chromosomes, and to reconstruct much of the evolutionary history of ancient and recent chromosome rearrangements leading to the modern human karyotype.
Figure Synteny maps. a, For each Tetraodon chromosome, coloured segments represent conserved synteny with a particular human chromosome. Synteny is defined as groups of two or more Tetraodon genes that possess an orthologue on the same human chromosome, irrespective of orientation or order. Tetraodon chromosomes are not in descending order by size because of unequal sequence coverage. The entire map includes 5,518 orthologues in 900 syntenic segments. b, On the human genome the map is composed of 905 syntenic segments. See Supplementary Information for the synteny map between Tetraodon and mouse (Supplementary Fig. S11).
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