在美國科學(xué)院院刊刊登的一則文章中，英國哥倫比亞大學(xué)植物學(xué)教授帕特里克?基林（Patrick Keeling）闡述了Chromera的基因組,，以及它在瘧疾和腰鞭毛蟲藻進(jìn)化歷史中扮演的角色,。
“在顯微鏡下,，Chromera就像是簡單的小褐色球，”基林說,。“其實(shí),，海洋中到處都是褐色和綠色的小球，它們常常因?yàn)橛懈嗝匀说挠袡C(jī)生物而被忽略掉,，但是它卻比它那些浮華的‘表兄弟’更有趣,。”
Chromera第一次被描述到是在2008年的《自然》雜志中，它在珊瑚中作為一種珊瑚的共生體被發(fā)現(xiàn),。盡管Chromera有一個(gè)分隔空間——質(zhì)體,，它和其他藻類及植物一樣能產(chǎn)生光合作用,，Chromera和包括瘧疾在內(nèi)的頂復(fù)門寄生蟲很接近。Chromera可能將這兩者聯(lián)系到一起,。
現(xiàn)在,，基林和博士生簡 揚(yáng)歐斯科維克（Jan Janouskovec）、博士后阿勒斯 霍拉克和來自捷克共和國的同事們一起,，已經(jīng)把Chromera的質(zhì)體基因組排序,，并且找到了傳承到頂復(fù)門寄生蟲和腰鞭毛蟲身上的特質(zhì)，這種特質(zhì)把這兩個(gè)后裔聯(lián)系在了一起,。
“這些微小的有機(jī)生物對(duì)人類的各個(gè)方面都產(chǎn)生了巨大影響,，”基林說。從某方面來說,，腰鞭毛蟲和Chromera對(duì)珊瑚共生使用的手段已經(jīng)變成了一個(gè)傳染機(jī)制,，如同瘧疾對(duì)人體健康細(xì)胞的影響。
“解析它們的進(jìn)化源頭不僅是解決一個(gè)長期存有爭(zhēng)議的科學(xué)問題,，也為對(duì)抗疾病和環(huán)境問題提供了至關(guān)重要的信息,。”(生物谷Bioon.com)
生物谷推薦原文出處：
PNAS doi: 10.1073/pnas.1003335107
A common red algal origin of the apicomplexan, dinoflagellate, and heterokont plastids
Jan Janou?koveca, Ale? Horáka, Miroslav Oborníkb, Julius Luke?b, and Patrick J. Keelinga,1
Jan Janou?koveca, Ale? Horáka, Miroslav Oborníkb, Julius Luke?b, and Patrick J. Keelinga,1
The discovery of a nonphotosynthetic plastid in malaria and other apicomplexan parasites has sparked a contentious debate about its evolutionary origin. Molecular data have led to conflicting conclusions supporting either its green algal origin or red algal origin, perhaps in common with the plastid of related dinoflagellates. This distinction is critical to our understanding of apicomplexan evolution and the evolutionary history of endosymbiosis and photosynthesis; however, the two plastids are nearly impossible to compare due to their nonoverlapping information content. Here we describe the complete plastid genome sequences and plastid-associated data from two independent photosynthetic lineages represented by Chromera velia and an undescribed alga CCMP3155 that we show are closely related to apicomplexans. These plastids contain a suite of features retained in either apicomplexan (four plastid membranes, the ribosomal superoperon, conserved gene order) or dinoflagellate plastids (form II Rubisco acquired by horizontal transfer, transcript polyuridylylation, thylakoids stacked in triplets) and encode a full collective complement of their reduced gene sets. Together with whole plastid genome phylogenies, these characteristics provide multiple lines of evidence that the extant plastids of apicomplexans and dinoflagellates were inherited by linear descent from a common red algal endosymbiont. Our phylogenetic analyses also support their close relationship to plastids of heterokont algae, indicating they all derive from the same endosymbiosis. Altogether, these findings support a relatively simple path of linear descent for the evolution of photosynthesis in a large proportion of algae and emphasize plastid loss in several lineages (e.g., ciliates, Cryptosporidium, and Phytophthora).
