據(jù)4月11日的《科學(xué)》（Science）雜志報道說,，新的研究顯示,，在動物腸道中存在的2個細菌品種正在融合成為另一種單獨的品種。這一情況可能開始于牲畜的馴化過程,，因為該過程使這兩種細菌在雞,、牛及其它動物體內(nèi)相遇。細菌間的基因交換是如此地頻繁,，因此很難為不同種類的細菌建立系譜,，而我們對細菌自然群體的生態(tài)學(xué)知識尚處于初始階段。雖然如此,，空腸彎曲菌與大腸彎曲桿菌仍然被看作是截然不同的細菌品種,，而這兩種細菌是引起世界范圍內(nèi)人類胃腸道炎癥的最常見的致病菌。
Samuel K. Sheppard及其同事對數(shù)個不同動物群體中的這2種細菌的基因序列進行了分析并得出結(jié)論,，即這些細菌的基因已經(jīng)混合到兩種細菌的基因組正在合二為一的程度,。文章的作者提出，先前存在于這兩個品種之間的屏障可能已在新的環(huán)境中消失 — 假如是這樣的話,，按照進化論的說法，這種新的環(huán)境可能就是指在適于焙烤的嫩雞或其它牲畜的腸道之內(nèi),。（來源：EurekAlert!中文版）
生物谷推薦原始出處：
（Science）,，Vol. 320. no. 5873, pp. 237 - 239，Samuel K. Sheppard,，Martin C. J. Maiden
Convergence of Campylobacter Species: Implications for Bacterial Evolution
Samuel K. Sheppard, Noel D. McCarthy, Daniel Falush,* Martin C. J. Maiden
The nature of species boundaries in bacteria remains controversial. In particular, the mechanisms of bacterial speciation and maintenance in the face of frequent genetic exchange are poorly understood. Here, we report patterns of genetic exchange that show two closely related zoonotic pathogenic species, Campylobacter jejuni and Campylobacter coli, are converging as a consequence of recent changes in gene flow. Population expansion into a novel ecological niche generated by human activity is the most probable explanation for the increase in genetic exchange between these species. Bacterial speciation can therefore occur by mechanisms analogous to those seen in metazoans, where genetic diversification and incipient speciation caused by ecological factors have been reported in several genera.
