ABSTRACT
The yeast-like symbionts are isolated and purified from the small brown planthoppers collected from five areas in China. The 18S rDNA sequences of them are determined. Combined with the sequences of other fungi, we have constructed a comprehensive phylogenetic tree. The results suggested that the taxonomic positions of the YLS are in the class Pyrenomycetes in the subphylum Ascomycotina and the YLS have the closest relationship with H. chrysospermus. The YLS of different areas in China and Japan may belong to different geographical populations of one species. We could also draw a conclusion that there are independent acquisitions of various symbionts in differentiated hosts.
Subject(s)
DNA, Ribosomal/chemistry , Insecta/microbiology , RNA, Ribosomal, 18S/genetics , Symbiosis , Yeasts/genetics , Animals , PhylogenyABSTRACT
In this paper we analysed the RFLP of mtDNA in Lanzhou (LZ) population of D. virilis. By reanalysing the RFLP data of our previous work on other natural populations of D. virilis, a phylogenetic tree was produced based on the UPGMA method. It shows three main clusters: the Northern populations (LZ QD), the East China populations (NJ, SH, NB) and the Southern population (QZ). With the mtDNA's RFLP data and the results of our former work on allozyme variation in natural populations of D. virilis, we suggest that there exists a latitudinal cline of genetic variation in natural populations of D.virilis. The mechanism for the maintenance of the observed latitudinal pattern is discussed.
