Studies on L-Lactate dehydrogenase genes and protein structure of Iguana iguana and molecular phylogenetics among reptiles
L-Lactate dehydrogenases (LDH) are ¡§house keeping¡¨ enzymes. The LDH isozymes are known to be a very stable, slow-evolving and suitable to be a model to elucidate the phylogenetic relationships among various species. The cDNA sequences of LDH-A4 (muscle) and LDH-B4 (heart) from green iguana (Iguana iguana) were determined. The results of isozyme electrophoresis demonstrated that there are two isoforms of Iguana iguana LDH-B isozyme and called LDH-B and LDH-b. The protein structures of LDH-B and LDH-b monomer were constructed, and these two proteins have the same structure except the 5 different amino acids. The phylogenetic relationships between green iguana and other vertebrates, whose LDH cDNA sequences published previously, were analyzed by phylogenetic tree construction methods Mega2 program as well as Phylip program. These results on the relationships among lizards indicate that Iguana iguana is closer to Sceloporus woodi than to Sceloporus undulates. The divergent times between Iguana iguana and Sceloporus woodi, Iguana iguana and Sceloporus undulatus were estimated about 98 and 188 million years, respectively. The sequences of mitochondrial DNA(12S, 16S and ND1) among these three lizards were also analyzed, and the results were consistent with the traditional phylogenetics that species in the same genus were closer. The unexpected relationship that different genus of Iguana iguana and Sceloporus woodi is closer than that within same genus of Sceloporus woodi and Sceloporus undulates by analyzing among vertebrates LDH isozymes remained to be further confirmed.
Advisor:Steven Shoei-Lung Li; Yow-Ling Shiue; Sin-Che Lee
School:National Sun Yat-Sen University
School Location:China - Taiwan
Source Type:Master's Thesis
Keywords:protein sequences evolution iguana reptile ldh
Date of Publication:07/05/2002