精靈箭毒蛙 (Ranitomeya imitator)的擬態斑紋產生的生殖隔離可能導致族群種化

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a)表示精靈箭毒蛙 (R. imitator)
b) 表示其model 皇冠箭毒蛙 (R. fantastica) 與 齊亞曼箭毒蛙 (R. variabilis)
c) 兩型的分佈與雜交帶是意圖
d) 雜交帶出現的精靈箭毒蛙的多態型
e) 研究區域

標題:Reproductive isolation related to mimetic divergence in the poison frog Ranitomeya imitator

摘要

In a mimetic radiation—when a single species evolves to resemble different model species—mimicry can drive within-species morphological diversification, and, potentially, speciation. While mimetic radiations have occurred in a variety of taxa, their role in speciation remains poorly understood. We study the Peruvian poison frog Ranitomeya imitator, a species that has undergone a mimetic radiation into four distinct morphs. Using a combination of colour–pattern analysis, landscape genetics and mate-choice experiments, we show that a mimetic shift in R. imitator is associated with a narrow phenotypic transition zone, neutral genetic divergence and assortative mating, suggesting that divergent selection to resemble different model species has led to a breakdown in gene flow between these two populations. These results extend the effects of mimicry on speciation into a vertebrate system and characterize an early stage of speciation where reproductive isolation between mimetic morphs is incomplete but evident.

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各種不同參數的比較結果


討論擬態、種化與族群遺傳研究目前只有毒蝶 (Heliconius)比較多,精靈箭毒蛙的例子與毒蝶的例子很相似,不同區域擬態不同的物種,但對於不同族群間的遺傳結構,基因有沒有在族群間交流還不清楚。這個研究透過比較各種參數,像是微衛星體、身體的顏色與樣式、雄性的體重等等,顯示這個族群間只有很狹隘的雜交帶,各族群間已經有十分顯著的差異。這跟毒蝶的例子相似,可能是一個因為擬態的斑紋侷限族群的分佈,進而產生地理隔離種化的例子。



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此圖說明不同擬態型的精靈箭毒蛙的遺傳結構
這樣的研究與毒蝶最大的差異就在於這是脊椎動物,對於演化歷程完全不同的兩個擬態系統來說,如果能找類似的作用機制,是不是就能替擬態在自然界的作用找到個通論了呢?相似的系統還有很多,期待未來的發展。

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