使用分子遺傳標記偵測白頭翁與烏頭翁可能的雜交子代

Detecting Obscure Hybrids of Chinese Bulbuls (Pycnonotus sinensis) and Taiwan Bulbuls (P. taivanus) with Molecular Markers

許祐薰(Yu-Hsun Hsu)

指導教授 ： 劉小如

國立臺灣大學/生命科學院/生態學與演化生物學研究所/碩士(2009年)

https://doi.org/10.6342/NTU.2009.01963

摘要

烏頭翁與白頭翁雜交產生的子代通常明顯帶有兩者特徵。近年在野外出現一些形態上極似烏頭翁，惟臉頰羽色晦暗的個體，研究人員暫時稱之為烏頭亞型。為釐清此種個體是否為雜交子代，本研究利用微衛星基因座和擴增片段長度多態性來區分烏、白頭翁，並使用這些標記分析烏頭亞型個體與烏、白頭翁的相似度。結果顯示所使用的九個微衛星基因座並無法區分烏頭翁與白頭翁；而分析138個擴增片段長度多態性的出現頻率，有21個片段能大致將烏、白頭翁區分開來。此21個片段所帶的訊息顯示，烏頭亞型的遺傳組成介於烏、白頭翁之間，但與烏頭翁比較相似。推測烏頭亞型個體乃雜交個體與烏頭翁回交產生的子代。因烏頭亞型在野外調查中容易被誤判為烏頭翁，可能導致調查者低估烏、白頭翁的雜交程度，也低估雜交帶給特有種烏頭翁族群數量的負面影響。

關鍵字

雜交 ； 烏頭翁 ； 白頭翁 ； 微衛星基因座 ； 擴增片段長度多態性

並列摘要

The endemic Taiwan bulbuls (Pycnonotus taivanus) have been hybridizing with Chinese bulbuls (P. sinensis) and produced hybrids with intermediate phenotypes. However, some bulbuls which look like Taiwan bulbuls except with darker face have been seen in Kenting region (referred to as gray-faced Taiwan bulbul in this report). I used a set of microsatellite loci and amplified fragment length polymorphism (AFLP) to discriminate between Chinese and Taiwan bulbuls and to verify if the gray-faced Taiwan bulbuls were their hybrids. The nine microsatellite loci I used could not distinguish between Chinese and Taiwan bulbuls, but 21 out of 138 AFLP fragments could roughly separate the two species. According to these 21 fragments, the gray-faced Taiwan bulbuls showed features of both bulbuls, but were closer to Taiwan bulbuls than to Chinese bulbuls. My results suggested that the gray-faced Taiwan bulbuls probably resulted from hybrids backcrossing with Taiwan bulbuls. Since the gray-faced Taiwan bulbuls are frequently misidentified as Taiwan bulbuls in the field, the degree of introgressive hybridization from Chinese to Taiwan bulbuls can be easily underestimated.

並列關鍵字

hybridization ； Taiwan bulbuls ； Chinese bulbuls ； microsatellite ； AFLP

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