中科院西高所博士后學(xué)者趙凱與合作導(dǎo)師趙新全研究員最近的一項(xiàng)研究結(jié)果表明同域的物種形成模式在青藏高原特有的高度特化裂腹魚類物種之間很可能已經(jīng)發(fā)生,?；诰€粒體標(biāo)記的系統(tǒng)地理學(xué)分析顯示,，青藏高原一個(gè)冰川湖泊特有的斜口裸鯉（Gymnocypris ecklonie scoliostomu）完全具備了物種在同域條件下起源的標(biāo)準(zhǔn),。研究推斷斜口裸鯉很可能起源自同域分布在遜木措湖的花斑裸鯉（G. e. eckloni）種群,，主要的分歧時(shí)間發(fā)生在大約 0.057 百萬年,。
系統(tǒng)發(fā)育和種群遺傳分析顯示,，在花斑裸鯉物種的所有地理種群之間,，遜木措湖的花斑裸鯉種群與同域分布的斜口裸鯉個(gè)體保持最近的親緣關(guān)系,，暗示它們擁有一個(gè)最近的共同祖先,，這一結(jié)果為檢驗(yàn)正在發(fā)生的同域物種形成機(jī)制提供了理想的模式。斜口裸鯉表現(xiàn)出比花斑裸鯉更低的遺傳多樣性,，而且更加新近的擴(kuò)張時(shí)間被檢測(cè)在新起源的斜口裸鯉種群中,。我們認(rèn)為斜口裸鯉很可能起源自目前同域分布在遜木措湖的花斑裸鯉種群，而不是通常假設(shè)的這個(gè)類群曾經(jīng)有一個(gè)廣泛的地理分布,，后來在其它地區(qū)被滅絕,。由于各自生態(tài)的特有性，斜口裸鯉和遜木措湖花斑裸鯉通過自然選擇促進(jìn)了同域條件下的種群分歧,。該研究為進(jìn)化生物學(xué)長(zhǎng)期爭(zhēng)論的同域物種形成理論提供了新的分子生態(tài)學(xué)證據(jù),，論文已發(fā)表在國(guó)際著名生態(tài)學(xué)期刊《分子生態(tài)學(xué)》（Molecular Ecology）上。（生物谷Bioon.com）
生物谷推薦原始出處：
Molecular Ecology Volume 18 Issue 17, Pages 3616 - 3628
The youngest split in sympatric schizothoracine fish (Cyprinidae) is shaped by ecological adaptations in a Tibetan Plateau glacier lake
KAI ZHAO*, ZI YUAN DUAN??, ZUO GANG PENG?§, SONG CHANG GUO*, JUN BING LI?, SHUN PING HE? and XIN QUAN ZHAO*
*Key Laboratory of Adaptation and Evolution of Plateau Biota (AEPB), Northwest Plateau Institute of Biology, Chinese Academy of Sciences, 810001 Xining, Qinghai, China , ?Laboratory of Fish Phylogenetics and Biogeography, Institute of Hydrobiology, Chinese Academy of Sciences, 430072 Wuhan, Hubei, China , ?Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, 100101 Beijing, China
Although new empirical evidence shows that sympatric speciation has occurred in some species, there are few indisputable model organisms for this process of speciation. The two subspecies (Gymnocypris eckloni eckloni and G. e. scoliostomus) of the schizothoracine Gymnocypris fish species complex from a small glacier lake in the Tibetan Plateau, Lake Sunmcuo, fit several of the key characteristics of the sympatric speciation model. We used combined mitochondrial control region sequences and the cytochrome b gene (1894 bp) to address the phylogenetics and population genetics of 232 specimens of G. e. eckloni and G. e. scoliostomus, as well as all of its closely related sister species. We found that: (i) a total of four old lineages were uncovered in the widespread G. e. eckloni, of which only one was shown to be shared with all G. e. scoliostomus individuals and (ii) the new subspecies (G. e. scoliostomus) evolved in Lake Sunmcuo from the ancestral G. e. eckloni population within approximately 0.057 Ma. These two taxa of the species complex are morphologically distinct, and reproductive isolation is further suggested. Ecological disruptive selection based on morphological traits (e.g. mouth cleft characters) and food utilization may be a mechanism of incipient speciation of two sympatric populations within Lake Sunmcuo. This study provides the first genetic evidence for sympatric speciation in the schizothoracine fish.
