Studies of the molecular evolution of COl

Abstract

<p> There has been an increasing value in the ability to describe the world's diversity for the purpose of enhancing research and conservatory efforts. Characterizing the level of heterogeneity of particular molecular markers and verifying its suitability as an identifier of new specimens provides a way of quantifying biodiversity. One such molecular marker is the mitochondrial cytochrome c oxidase subunit I (COl). An analysis of the evolutionary rates among and within taxonomic groupings of 13,641 insect COl sequences revealed that the evolutionary rate of some species increased or decreased, sometimes by an order of a magnitude. Furthermore, the increased evolutionary rates of two species, from the Lepidopteran and Orthopteran orders, may be explained by the influence of positive selection but further analyses would be required to rule out other explanations. Overall, we deem that the rate of substitution generates enough change for COl to work sufficiently as a barcode marker in insects. As COl is not suitable for specimen identification in plants, it would be useful to be able to quickly determine if there is enough variation in COl or other molecular markers for specimen identification. In response, a visualization tool, Fingerprint, was developed to graphically depict 11 different types of sequence diversity. An application of the tool to Lepidopteran COl data verified the genetic diversity in insect COl and the tool's ability to sensitively detect different types of heterogeneity. </p>