鹿角蝴蝶蘭 Phalaenopsis cornu-cervi 含 (GA)n 微衛星體序列之選殖與定位

Abstract

微衛星體序列在真核生物基因組中含量豐富。以(GA)11為引子進行單引子聚合酶連鎖反應，從鹿角蝴蝶蘭Phalaenopsis cornu-cervi分離出11個富含(GA)n之微衛星體序列，序列長度在120~860 bp之間，序列間平均相似度為54.45%，TIGR資料庫序列比對結果與許多植物之重複性序列相類似。5個選殖體W8-4、W8-5、W8-18、W8-35與W8-41、朵麗蘭（Phalaenopsis pulcherrima）之DpGA2和Phalaenopsis stuartiana 分離的W40-19利用螢光原位雜交實質定位的結果，皆位於鹿角蝴蝶蘭所有染色體的中節，且訊號強度相似。過去DpGA2定位結果，只位於朵麗蘭一對染色體的中節，有明顯差異。W8-18訊號亦位於 P.stuartiana、Phalaenopsis mannii 與朵麗蘭染色體的中節，且以P.stuartiana染色體中節的訊號最強，此與過去利用人工合成(GA)11定位的結果相吻合。

Microsatellites are highly abundant in eukaryotic genomes. Eleven (GA)n microsatellite-containing clones were isolated from Phalaenopsis cornu-cervi by single-primer PCR using (GA)11 as a primer. The size of sequences varied from 120 to 860 bp and the average sequence identity for those was 54.45%. Sequence homology searches of the TIGR database revealed similarities with repetitive sequences in many plants. Seven clones, W8-4, W8-5, W8-18, W8-35, and W8-41 from P. cornu-cervi, DpGA2 from P. pulcherrima, and W40-19 from P. stuartiana, were all mapped in the metaphase chromosomes of P. cornu-cervi by fluorescence in situ hybridization (FISH). All signals were similar in intensity and clustered in the centromeric regions of all chromosomes. It was found a quite exceptional distribution of DpGA2 probe which was only located in the centromeric regions of one chromosome pair of P. pulcherrima. The hybridization signals of the clone W8-18 were also clustered in the centromeric regions of P. mannii, P. pulcherrima, and P. stuartiana chromosomes. In addition, signals were much stronger in P. stuartiana than in other species. These results were consistent with the physical mapping of synthetic oligonucleotides (GA)11 in the previous study.