Phylogenetic relationships Comparative studies

We will discuss some of our comparative sterol metabolism studies and provide specific examples to illustrate some of these unusual variations in steroid utilization and metabolism in insects, and to show how this information is useful in predicting differences in ecdysteroid biosynthesis in certain species. We will also point out instances in which these variations in neutral sterol metabolism can be related to phylogenetic relationships between species. 

The phylogenetic analysis of known coronins presents a comprehensive overview of this gene family and lays a foimdation to advance studies on their distribution, structure and functional diversity in other species. The knowledge of evolutionary relationships should facilitate comparative genomic studies that will help to elucidate the fundamental cellular roles of coronins and rationalize their apparent absence from plants, which are also distinguished by their exceptionally high ratio of monomeric to filamentous actin. The diversity of coronins in unicellular organisms... 

The presence or absence of the ability to synthesize certain fatty acids may then serve as a basis for establishing relationships between species. The value of the study of the comparative biochemistry of fatty acid synthesis depends on the point on the evolutionary time scale when the ability to synthesize a particular fatty acid appeared. There is no reason why the same gene mutation should not occur in different groups at different times. But while a comparatively recent mutation may be of little interest to the comparative biochemist, certain mutations which occurred in the early evolution of primitive organisms may be useful in enabling phylogenetic pathways to be traced. 

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