부산대학교 도서관

Summary: Single-fly polymerase chain reaction amplification and direct DNA sequencing revealed high levels of length polymorphism in the threonine-glycine encoding repeat region of theperiod (per) gene in natural populations ofDrosophila melanogaster. DNA comparison of two alleles of identical lengths gave a high number of synonymous substitutions suggesting an ancient time of separation. However detailed examination of the sequences of different Thr-Gly length variants indicated that this divergence could be understood in terms of four deletion/insertion events. InDrosophila pseudoobscura a length polymorphism is observed in a five-amino acid degenerate repeat, which corresponds tomelanogaster's Thr-Gly domain. In spite of the differences betweenD. melanogaster andD. pseudoobscura in the amino acid sequence of the repeats, the predicted secondary structures suggest evolutionary and mechanistic constraints on theper protein of these two species.