Exploring the Molecular Landscape of Host-Parasite Coevolution

Abstract

Host-parasite coevolution is a dynamic process that can be studied at the phenotypic, genetic, and molecular levels. Although much of what we currently know about coevolution has been learned through phenotypic measures, recent advances in molecular techniques have provided tools to greatly deepen this research. Both the availability of full-genome sequences and the increasing feasibility of high-throughput gene expression profiling are leading to the discovery of genes that have a key role in antagonistic interactions between naturally coevolving species. Identification of such genes can enable direct observation, rather than inference, of the host-parasite coevolutionary dynamic. The Daphnia magna-Pasteuria ramosa host-parasite model is a prime example of an interaction that has been well studied at the population and whole-organism levels, and much is known about genotype- and environment-specific interactions from a phenotypic perspective. Now, with the recent completion of genome sequences for two Daphnia species, and a transcriptomics project under way, coevolution between these two enemies is being investigated directly at the level of interacting genes.

Gain and loss of multiple functionally related, horizontally transferred genes in the reduced genomes of two microsporidian parasites

“…It also is noteworthy that all but one of these genes is found in subtelomeric regions of E. hellem and E. romaleae. These poorly studied genomic regions usually evolve faster than the chromosome cores and often are associated with rapid biological innovation, such as parasites coevolving with their hosts' immune systems (25,26), and in other cases have been observed to be rich in genes derived from HGT (27). Given the compactness of Encephalitozoon genomes, it also is more likely that recombination into the chromosome cores would disrupt vital sequence information (e.g., any random insertion is about 10 times more likely to hit a gene than to hit an intergenic region).…”

Polymorphisms at the innate immune receptorTLR2are associated withBorreliainfection in a wild rodent population

“…Despite this, there is typically significant genetic variation for resistance to parasites and pathogens in natural populations [1]. To elucidate the evolutionary causes and consequences of such variation, a better understanding of which genes actually contribute to variation in resistance is desirable [2][3][4]. However, whereas there is a considerable body of literature on the genetic basis of resistance in humans [5], knowledge from other animals, and in particular from natural vertebrate populations, is as yet very limited (but see [6]).…”

Identification of Spodoptera exigua nucleopolyhedrovirus genes involved in pathogenicity and virulence

“…The genotypic variation in baculovirus populations has been associated with differences in phenotypic traits such as pathogenicity, virulence and occlusion body (OB) productivity (Erlandson, 2009). A comparison of the genomes of phenotypically distinct virus strains can be used to identify genes involved in these traits (Allen and Little, 2009), and guide the selection of strains or development of recombinant viruses with improved insecticidal properties as compared to the wild-type parental viruses.…”