The Wiegmann Lab

Dipteran Molecular Systematics at North Carolina State University

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- RESEARCH -

Insect Molecular Systematics at NCSU

Our research in molecular biosystematics is aimed at inferring phylogenetic relationships and testing hypotheses about the evolution and diversification of insects. A major focus is reconstruction of the family-level phylogeny of the insect order Diptera (true flies). A major component of these studies is uncovering patterns and processes of DNA sequence evolution and using these to improve interpretation of morphological and developmental evolutionary pathways.

 

Current Research Focal Areas

Molecular Phylogenetics of Diptera: FLYTREE - NSF - Assembling the Tree of Life project on Diptera a Collaborative Research Effort in Dipteran Phylogenetics

The need for new, large, comprehensive datasets for Diptera phylogeny motivates our collaborative, National Science Foundation funded, Assembling the Tree of Life (ATOL) project-- FLYTREE. Within this study, we are assembling multiple phylogenetic data sets to simultaneously assess dipteran phylogenetic relationships and the information content of specific character systems. For example, we will compare large “by character” data sets (1st tier; 45 taxa; 15-20 genes and mt genomes) to those with increased numbers of taxa (“by taxa”) (2nd tier; 250 taxa; 3-8 genes). Phylogenetic results from these datasets will be compared to newly collected morphological data and to supertree analyses across the entire order.

Click here to learn more about the FLYTREE Project and to use our latest results and web products.

 

Nuclear Genes for Holometabolan insect phylogenetics

Building on data generated in the NSF ATOL FLYTREE project, the insect genome projects, and the Deep Arthropod ATOL, we are developing and screening primers for proteins and protein coding genes that may prove informative for phylogenetic studies within and between holometabolan orders. Two major questions we are currently addressing are the phylogenetic sister group of the Diptera, and a comprehensive molecular phylogeny of the the Neuroptera with Shaun Winterton, CDFA, Sacramento.

 

The Evolutionary History of brachyceran fly diversification

Divergence time estimation from nucleotide sequence data provides an important link between paleontology and molecular systematics. It sheds light on the origin and timing of cladogenesis in the absence of complete fossil histories. The flourishing of molecular systematic methodology and a wealth of molecular data are leading to more accurate age estimates. Divergence time methods have traditionally assumed that the rate of molecular evolution is constant, and are termed clock-based approaches. Several recently proposed methods that do not assume constant rates of evolution have been proposed. These non-clock methods are potentially more accurate than clock-based strategies, especially when the relationships under study span a broad range of ages and taxonomic levels, or have undergone one or more significant radiations. We have been conducting collaborative work on Bayesian diversification time methods with Jeffrey Thorne, NCSU Statistical Genetics.

Bracyceran fly phylogeny provides an ideal system for reconstructing divergence times from molecular sequence data. Until very recently, the fossil record for Mesozoic Diptera has been too sparse to provide dates for most of the clades surrounding the origin and diversification of the higher-flies (Hennig 1981; Labandeira 1994; Evenhuis 1994). However, the sample of fossils from key brachyceran clades has recently surged (Grimaldi and Cumming 1999; Ren 1998a, b). This fossil evidence provides a framework of minimum clade ages that will allow improvement and evaluation of the non-clock methods.

 

Collaborative research on the phylogeny of ...

The earliest fly lineages

Therevidae

Empidoidea

Asiloidea

Acroceridae

Agromyzidae

Muscidae

Clusiidae

Tabanidae