[Random amplified polymorphic DNA (RAPD) analysis of Drosophila simulans in the mainland of China].
The widespread distribution of Drosophila simulans in the mainland of China was found recently. Random amplified polymorphic DNA (RAPD) was used to analyzed DNA polymorphisms of 38 Drosophila simulans populations collected from the mainland of China. The origins of D. simulans in China were also discussed. Using 40 arbitary primers (10 bp), we made PCR amplifications under the optimized reaction conditions for RAPD that had been established in our laboratory. Our molecular phylogenetic tree constructed by UPGMA method showed as follows: (1) 38 populations are apparently classified into Northern cluster and Southern cluster, where NJ(Nanjing) can be considered as the boundary according to latitude. The populations in the Northern cluster can be further grouped into two sub-clusters, where BJ(Beijing) can be considered as the boundary according to latitude. The Northeast one consists of 10 populations, including Mohe(MH), Hailaer(HLR), Heihe(HH), Jiamusi(JMS), Haerbin(HRB), Changchun(CC), Shenyang(SY), Dandong(DD), Yanji(YJ), Tumen(TM); the other consists of 12 populations, including Beijing (BJ), Datong(DT), Huhehaote(HHHT), Yinchun(YC), Xinin(XN), Lanzhou(LZ), Taiyuan(TY), Shijiazhuang(SJZ), Yantai (YT), Jinan(JN), Xuzhou(XZ), Lianyungang(LYG). The southern cluster consists of the left 16 populations, including Zhengzhou (ZZ), Wuhan(WH), Shanghai(SH), Nanjing(NJ), Hangzhou(HZ), Chongqing(CQ), Nanchang(NC), Wenzhou(WZ), Changsha (CS), Guiyang(GY), Fuzhou(FZ), Kunming(KM), Xiamen(XM), Guangzhou(GZ), Nanning(NN), Hainan(HN). (2) The genetic distances among populations relate to the collection sites to a great extent, though there are some exceptions. According to the facts that we know, (1) D. simulans is an exotic species; (2) The invasion of D. simulans in the mainland of China took place in recent 30 years or so. (3) The widespread distribution of D. simulans in the mainland of China started in recent 10 years or so. Therefore, the results above might not be due to geographical differentiation, but due to genetic differences of initial founder individual(s) between geographical populations. Some of geographically adjacent populations, however, have common initial founder individual(s), which results in the classification of D. simulans populations according to their geographical relationship. We suggest that there are two possible reasons which result in the genetic differences of initial founder individual(s) between geographical populations, one is the D. simulans in the mainland of China had multiple origins, the other is founder effect and/or bottleneck effect that the D. simulans have experienced in the course of expansion.
Xu
Shu-Hua
SH
Faculty of Life Science, Hubei University, Wuhan 430062, China.
Zeng
Qing-Tao
QT
Qian
Yuan-Huai
YH
Li
Shou-Tao
ST
Yang
Yong
Y
D000818:Animals; D002681:China; D004330:Drosophila / Q000145:classification / Q000235:genetics*; D010802:Phylogeny; D019105:Random Amplified Polymorphic DNA Technique