利用螢光原位雜交探討微衛星體序列在蝴蝶蘭的實質分佈

Abstract

微衛星體序列是以1-6 bp為組成單位的簡單重複性序列，普遍存在於真核生物的基因組中。本實驗以六種人工合成的微衛星體序列為探針，與七種蝴蝶蘭原生種Phalaenopsis amabilis var. formosa、P. stuartiana、P. equestris、P. lueddemanniana、P. amboinensis、P. violacea、P. mannii及一種朵麗蘭Doritis pulcherrima基因組DNA進行南方氏雜交和螢光原位雜交。南方氏雜交的結果，除(CAC)7序列外，其餘五種序列(AT)10、(CA)11、(GA)11、(GAA)7與(GATA)6，普遍存在於八種蝴蝶蘭的基因組中，且前三種序列的含量較多。螢光原位雜交的結果，(AT)10與(CA)11序列是屬於散佈型的重複性序列；(GA)11序列在P. amboinensis與P. violacea亦屬於散佈型，而在其餘六種蝴蝶蘭訊號集中於染色體中節處，是屬於聚集型。

Microsatellites consisting of tandemly repeated arrays of 1-6 nucleotide motif are ubiquitous in most eukaryotic genomes. In this study six microsatellites were used to investigate the physical distribution among seven Phalaenopsis species and the closely related species Doritis pulcherrima. Signals of various strength were detected in all tested plant genome as hybridized to motifs (AT)10, (CA)11, (GA)11, (GAA)7 and (GATA)6 but not (CAC)7. The motifs (AT)10, (CA)11 and (GA)11 were selected for examining physical distribution with fluorescence in situ hybridization because strong signals were resulted from them. It revealed that (AT)10 and (CA)11 were widely dispersed on all chromosomes of eight orchids. (GA)11 was also dispersed on chromosomes of P. amboinensis and P. violacea, but signals were mainly restricted to centromeric regions in other six orchids.