Molecular evolution and species biology
The POPPHYL (Population phylogenomics: Linking molecular evolution to species biology) project set out to characterise the population genetics of many different representatives of plant and animal species. The aim was to discover which biological and ecological factors determine molecular evolutionary processes, thereby explaining why genomes evolve the way they do. Next-generation sequencing technologies were used to produce massive coding sequence polymorphism data sets for 90 ecologically diverse animal species. This enabled scientists to compare the population genetic parameters relevant to molecular evolution among different taxa such as mammals, birds, turtles, insects, molluscs, worms and jellyfish. The organisms studied included pests (termites), vectors of disease (mosquitoes), commercial fishery species (blue mussels), ecosystem engineers (corals) and endangered species (like the Galapagos tortoise). The scientific curiosity Lineus longissimus, which is a marine worm that grows up to 60 m long, was also studied. Results show the processes of molecular evolution and highlight the major effect of population size and genetic drift on the rates of molecular evolution. Analysis of the entire data set revealed that the genetic diversity of a species (meaning the extent to which individuals belonging to the same species differ from each other) is determined by key ecological traits related to parental investment. Long-lived species known as k-strategists that invest in fewer offspring, each of which has a relatively high probability of surviving to adulthood, were found to be genetically less polymorphic than r-strategists. The r-strategists are short-lived species with a high growth rate that produce many offspring. This finding indicates that the long-term life history strategy of species influences their response to short-term environmental perturbations. POPPHYL explored the link between phylogenetics and population genetics. This brought a new dimension to evolutionary biology by making population genetics comparative and applying species ecology to genomic analyses. The results will have immediate implications for the field of conservation biology.
Keywords
Molecular evolution, species biology, population genomics, POPPHYL, phylogenomics
