The intraspecific difference of the triose phosphate isomerase (tim) gene from Giardia lamblia.
OBJECTIVE
To investigate the intraspecific difference of the triose phosphate isomerase (tim) gene from Giardia lamblia (G. lamblia).


METHODS
Total genomic DNA of G. lamblia was extracted and partial fragments of the triose phosphate isomerase (tim) gene were amplified by polymerase chain reaction (PCR). All nucleotide sequences were analyzed by using a phylogenetic analysis, which was constructed with parsimony and Neighbor-joining (N-J) methods.


RESULTS
A total of 124 variable sites (23% of all sequences detected) was defined, most of which were found at the silent sites of codons. Two similar phylogenetic trees were constructed, subdividing 16 Giardia isolates into two groups.


CONCLUSIONS
The genetic diversity of G. lamblia appeared to be little affected by factors of both host and geography, while natural-selection played an important role in DNA molecular evolution level of the tim gene. The tim gene may be considered a very useful genetic marker of the population genetic structure of G. lamblia.
Department of Cell Biology, the Capital University of Medical Sciences, Beijing 100054, China. Lusiqi@cpums.edu.cn
Siqi
S
Lu
Jihong
J
Li
Yaping
Y
Zhang
Jianfan
J
Wen
Fengyun
F
Wang
D000818:Animals; D001483:Base Sequence; D016054:DNA, Protozoan / Q000737:chemistry / Q000235:genetics; D016829:Giardia lamblia / Q000201:enzymology / Q000235:genetics*; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid; D013045:Species Specificity; D014305:Triose-Phosphate Isomerase / Q000235:genetics*
D016054:DNA, Protozoan; D014305:Triose-Phosphate Isomerase