Abstract.
The lactate and malate dehydrogenases comprise a complex protein superfamily with multiple enzyme homologues found in eubacteria, archaebacteria, and eukaryotes. In this study we describe the sequence and phylogenetic relationships of a malate dehydrogenase (MDH) gene from the amitochondriate diplomonad protist, Giardia lamblia. Parsimony, distance, and maximum-likelihood analyses of the MDH protein family solidly position G. lamblia MDH within a eukaryote cytosolic MDH clade, to the exclusion of chloroplast, mitochondrial, and peroxisomal homologues. Furthermore, G. lamblia MDH is specifically related to a homologue from Trichomonas vaginalis. This MDH topology, together with published phylogenetic analyses of β-tubulin, chaperonin 60, valyl-tRNA synthetase, and EF-1α, suggests a sister-group relationship between diplomonads and parabasalids. Since these amitochondriate lineages contain genes encoding proteins which are characteristic of mitochondria and α-proteobacteria, their shared ancestry suggests that mitochondrial properties were lost in the common ancestor of both groups.
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Received: 14 September 1998 / Accepted: 29 December 1998
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Roger, A., Morrison, H. & Sogin, M. Primary Structure and Phylogenetic Relationships of a Malate Dehydrogenase Gene from Giardia lamblia . J Mol Evol 48, 750–755 (1999). https://doi.org/10.1007/PL00006519
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DOI: https://doi.org/10.1007/PL00006519