蝴蝶蘭兩種重複性DNA序列的分離與定性

Abstract

我們從Phalaenopsis violacea的基因組DNA中分離出兩種重複性DNA序列，Pvr Ⅰ及Pvr Ⅱ，並分析了其核?酸序列、種間分佈及在染色體上的位置。PvrⅠ族重複性序列是由兩端富AT序列的區域及中間7 bp頭尾相接的重複性序列（GTAAGCC）13-22所組成。經南方氏雜交及螢光原位雜交得知，PvrⅠ族僅存在於含大染色體的P. mannii、P. amboinensis、P. venosa、P. violacea及Doritis pulcherrima的基因組中，且多聚集在大染色體末端AT含量豐富的異染色質區域。PvrⅡ族重複性序列則在八種原生種的基因組中皆存在，以選殖體Pvr-95為探針，經螢光原位雜交得知，此序列散佈於P. venosa的所有染色體中。

Two repetitive DNA sequences, Pvr Ⅰ and Pvr Ⅱ, were isolated from Phalaenopsis violacea and characterized. The Pvr Ⅰ family consists of AT-rich regions at 5' and 3' ends and 7 bp direct subrepeats (GTAAGCC)13-22. Southern analysis and fluorescence in situ hybridization (FISH) revealed that Pvr I is present in P. mannii, P. amboinensis, P. venosa, P. violacea and Doritis pulcherrima and mostly located in the AT-rich subtelomeric heterochromatin of large chromosomes. The Pvr Ⅱ family is present in all eight Phalaenopsis species studied. FISH using one clone (Pvr-95) as a probe showed that Pvr Ⅱ is dispersed on all chromosomes of P. venosa.