Genetic diversity assessments in the century of genome science

Genetic elements determine phenotypes of organisms by interacting with environments. Despite genetic diversity within and between species being the fundamental basis of biological diversity, its contribution has been long neglected in biodiversity studies. This situation is rapidly changing as quantification of genetic diversity, from intraspecific up to the ecosystem level, has become more accessible owing to the development of next-generation sequencing technologies (NGSTs). Whole-genome sequencing techniques provide two specific approaches for accessing genetic diversity at large scales: metagenomics (environmental genomics) and EST (Expressed Sequence Tag) comparisons. The former has been applied successfully in the profiling of different microbial biomes, and it is particularly interesting in understanding their ecosystem structure and function. The latter is particularly useful in the studies of adaptation and the assessment of functional traits. Unquestionably, advances in the genomic sciences combined with a new generation of ecological and evolutionary science will boost new approaches to global and local assessments of biodiversity changes, and more importantly, will surely reframe the questions we are asking in biodiversity science.