The Genomic Basis of Morphological & Taxonomic Diversity

By investigating variations in the genome linked to specific phenotypic differences within or among species—i.e., comparative genomics—one can systematically pinpoint the heritable units of evolution responsible for the observed biodiversity today. Our research delves into the identification of highly diversified genomic regions, or genomic islands, examining their emergence and submergence across evolutionary time and geographic space. Moreover, our focus extends to understanding the differentiation of these genomic regions between taxa, such as structural variations, and exploring whether these regions are correlated with loci known to impact specific morphological traits.

Speciation & Species Delimitation

Speciation can be a continuous and multidimensional process. Divergences between diverged and between diverging taxa (e.g., populations/ecotypes/geographic isolates/subspecies/species) can occur and accumulate along different axes (e.g., genetic, phenotypic, and ecological differences) with different rates. Our research focuses on utilizing multiple data sets/types to study the speciation histories. Based on integrative approaches and the understanding of how divergences were initiated and completed, our study results can be used to make biologically and evolutionarily informed and coherent decisions to define species boundary. 

The Prevalence & Consequence of Genetic Interchange

How often do we see genetic interchange between diverging (e.g., populations; gene flow) and between fully diverged (e.g., species; genetic introgression) evolutionary units and under what condition do we expect genetic interchange to occur have been intensively debated in evolutionary biology. We study genetic introgression and gene flow using evolutionary lineages with distinct life histories (e.g., beetles & lichens) and that their diversifications were driven by different historical processes (e.g., ecological & allopatric speciation). The study results are not only critical to determine the frequency and extent of genetic interchange, but also to understand how and why such event occurs. We are also interested in understanding whether genetic interchange can impede or promote speciation, and whether such event can create evolutionary novelty that facilitate subsequent adaptive evolution.

Phylogeography, Biogeography, & the Interface

We are particularly interested in the geographic aspect of biodiversity variation. Specifically, how does a specific barrier type, say oceanic barrier on terrestrial organisms, impact intraspecific and interspecific genetic divergences. Our research focuses on testing whether the effect of a specific barrier type is concerted across different levels of biodiversity (e.g., population structure, species divergence, and community assembly). Implications for the study are (1) whether factors that initiate population subdivision also help to complete speciation, and (2) whether speciation is fundamentally a different process from population subdivision.

Conservation & Biological Invasion

A practical aspect of studying biodiversity is to identify evolutionary units that merit conservation efforts (i.e., evolutionary significant units; ESU). Genetic, and particularly genomic, data not only can help us identify endemic lineages, but also estimate the effective population size and the demographic history of the species of interest. The results are important to inform conservation plans.

Range expansions, novel phenotypes, multiple introductions, and colonizing new niches are commonly observed among invasive species. The specific properties make Invasive species great examples to study the phenotypic and genetic consequences of rapid environmental changes (i.e., evolution in real time). The results can help us understand how species react to climate change and how to protect endemic biota facing global biological invasion.