On the Low Genetic Variability in Drosophila Immigrans and D. Formosana

大果蠅（Drosophila immigrans）與臺灣大果蠅（D. formosana）之低遺傳變異性

張慧羽(Hwei-Yu Chang) ； 丁照棣(Chau-Ti Tinq) ； 林飛棧(Fei-Jann Lin)

《Zoological Studies》 33卷4期 (1994/10) Pp. 287-295

摘要

不論用粒腺體DNA、染色體逆位或酯酶的異構酶來當指標，同胞種臺灣大果蠅（Drosophila formosana）和大果蠅（D. immigrans）均呈現極低的遺傳變異性。這個結果和紅果蠅（D. albomicans）相比，可以得到下面的推論：（1）這三個指標在顯示遺傳變異性上是一致的；（2）這一對同胞種的低遺傳變異性是由於這二種在臺灣立足時為小族群及在臺灣的歷史不長所致，而不是受環境限制所塑造的。此外，由調查中顯示，此二同胞種雖然在實驗室可雜交且雜交後代部份可孕，但由粒腺體DNA及酯酶電泳二項指標都顯示自然族群無遺傳漸滲（Introgression）的現象。

關鍵字

染色體逆位 ； 酯酶 ； 拓荒者效應 ； 遺傳變異 ； 粒腺體DNA限制酶切型

並列摘要

Restriction patterns of mitochondrial DNA, esterase isozyme electromorphs, and chromosome inversions were chosen as indicators to investigate the genelic variability of natural populations of a sibling species pair, Drosophila immigrans and D. formosana, in Taiwan. In addition to local populations, we also surveyed sixteen laboratory-maintained stocks of the cosmopolitan species D. immigrans originating from different countries. All three indicators consistently showed that the local populations of both species in Taiwan have a very low genetic variation. No trace of introgression was found although they can produce fertile hybrids. The low genetic variability of these two species may be due to both the founder effect and their recent establishment in Taiwan.

並列關鍵字

Chromosome inversions ； Esterase isozymes ； Founder effect ； Genetic variation ； MtDNA restriction patterns