Population genetic structure of Bufo melanostictus in Changhua County analyzed by mitochondrial DNA D-loop partial fragment

• Main Authors: Yun-Ru Li, 李韻如
• Other Authors: Ling Jiang
• Format: Others
• Language: en_US
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/26482345800151242192

碩士 === 國立彰化師範大學 === 生物學系 === 95 === The mtDNA partial D-loop sequences of Asian common toads, Bufo melanostictus, in Changhua County was applied to evaluate the effect of distance and landscapes on their genetic structure and compare with its sympatric species Rana limnocharis for providing information on conservation. 252 and 120 animals from 20 and 15 sampling sites locating in Changhua County and other counties of Taiwan were directly sequenced and analyzed. Among 368-bp fragments, there were 14 and 18 variable sites composing 12 and 19 haplotypes in Changhua County and other counties in Taiwan, respectively. Two distinct groups of haplotypes, H1 group and H5 group, implied there were two origins of Asian common toad population in Taiwan. Distribution of haplotypes suggested that ancestors with H1 haplotype group developed populations and dispersed earlier than ancestors of H5 haplotype group. Results of higher genetic diversity in Asian common toads (h=0.81, π=0.008) in Taiwan also supported the criterion of IUCN that B. melanostictus was free from rapid declining. However there was highly differentiated among populations in Taiwan besides Changhua County (ΦST=0.53, FST=0.52). Since Isolation-By-Distance (IBD) effect was significant among other counties in Taiwan, high population differentiation was mainly leaded from large geographical distance preventing gene flow. Within Changhua County, absent of IBD effect (P>0.5) suggested that significant high genetic differentiation (ΦST=0.18, FST=0.19) was not depending on geographical distance. Comparison between B. melanostictus and R. limnocharis suggested that both species (h>0.5, π<0.5%) were under population expansion. Higher population differentiation in Asian common toads (ΦST=0.18, FST=0.19) was probably due to criticism for breeding ponds.