圖片來源：dendro.mojzisek.cz文獻來源: Valade R, Kenis M, Hernandez-Lopez A, Augustin S, Mari Mena N, Magnoux E, Rougerie R, Lakatos F, Roques A, Lopez-Vaamonde C. 2009. Mitochondrial and microsatellite DNA markers reveal a Balkan origin for the highly invasive horse-chestnut leaf miner Cameraria ohridella (Lepidoptera, Gracillariidae). Molecular Ecology 18(16): 3458 - 3470. [Abstract]
生物入侵通常始於少量的創始者個體。創始者很可能只表現出來源族群一小部分的遺傳多樣性。本研究以遺傳方式追蹤七葉樹潛蛾（Cameraria ohridella，一種起源地未明的入侵性小鱗翅目昆蟲）的地理起源。自從25年前在馬其頓的發現後，這種昆蟲經歷了爆炸性的向西擴張，日益拓殖到整個中歐與西歐。作者使用COI序列（DNA條碼片段）與一組六個多型性的微衛星體去評估七葉樹潛蛾族群的遺傳變異，並測試七葉樹潛蛾起源自南巴爾幹半島（阿爾巴尼亞、馬其頓和希臘）的假說。來自88的地點共486個樣本的mtDNA讓我們鑑定出了25個地理結構上的單體型。此外，來自歐洲與南巴爾幹半島的 16個族群、共480個個體在基因上被找出6個多型性的微衛星體基因座。單體型具有高多樣性而核甘酸多樣性測量值低、包括顯著負相關的 Tajima’s D指數，表示七葉樹潛蛾在擴散橫越歐洲時曾經歷快速的族群擴張。粒線體與微衛星體DNA均顯示來自歐洲人為棲地（如公園、花園中的植樹或道路兩邊的空地）的七葉樹潛蛾與來自南巴爾幹半島自然棲地的樣本相較，有遺傳多樣性減低的現象。作者根據以上發現推測，歐洲的七葉樹潛蛾族群的確源自於南巴爾幹半島。
Abstract
Biological invasions usually start with a small number of founder individuals. These founders are likely to represent a small fraction of the total genetic diversity found in the source population. Our study to trace genetically the geographical origin of the horse-chestnut leafminer, Cameraria ohridella, an invasive microlepidopteran whose area of origin is still unkown. Since its discovery in Macedonia 25 years ago, this insect has experienced an explosive westward range expansion, progressively colonizing all of Central and Western Europe. We used cytochrome oxidase I sequences (DNA barcode fragment) and a set of six polymorphic microsatellites to assess the genetic variability of C. ohridella populations, and to test the hypothesis that C. ohridella derives from the southern Balkans (Albania, Macedonia and Greece). Analysis of mtDNA of 486 individuals from 88 localities allowed us to identify 25 geographically structured haplotypes. In addition, 480 individuals from 16 populations from Europe and the sout ern Balkans were genotyped for 6 polymorphic microsatellite loci. High haplotype diversity and low measures of nucleotide diversities a significantly negative Tajima’s D indicate that C. ohridella has experienced rapid population expansion during its dispersal across Europe. Both mtDNA and microsatellites show a reduction in genetic diversity of C. ohridella populations sampled from artificial habitats (e.g. planted trees in public parks, gardens, along roads in urban or sub-urban areas) across Europe compared with C. ohridella sampled in natural stands of horse-chestnuts in the southern Balkans. These findings suggest that European populations of C. ohridella may indeed derive from the southern Balkans.
Keywords: Aesculus hippocastanum, Balkans, Cameraria ohridella, genetic bottleneck, invasion, phylogeography
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