Patel Lab Research Summary

Over the past two decades, developmental biologists have made great strides in understanding embryonic pattern formation at the genetic, molecular, and cellular levels. Much of this advancement can be attributed to the remarkable success of studies of pattern formation in model systems, such as the fruit fly Drosophila melanogaster. Identification of genes that play major roles in setting up the body plan, combined with the subsequent discovery that many of these genes are well conserved even between different phyla, has also led to a renaissance in the investigation of the links between evolution and development. Using information collected from studies of Drosophila development, my lab and others are beginning to explore the degree to which developmental pathways have been conserved or altered between various arthropods. Insights into the nature of developmental and molecular alterations will help us to understand the evolutionary changes in the mechanisms of pattern formation and provide a molecular basis for analyzing the diversification of body morphologies and developmental mechanisms.

The current work in the Patel Lab can be divided into three main project areas:

  1. The role of homeotic (Hox) genes in the evolution of body morphology
  2. Germ line regeneration in Parhyale hawaiensis
  3.  Structural color in Butterflies

For a list of past research projects, please see … past research.

And for a list of publications, click … publications.

Role of Hox genes in the evolution of body morphology

The Hox genes are known to play a major role in specifying regional identity along the anterior-posterior axis of animals from a wide range of phyla (Manak and Scott, 1994). Their potential role in altering body plan during evolution was recognized soon after their characterization (Lewis, 1978). For example, since altering the regulation of the Hox gene Ultrabithorax (Ubx) transforms a normally two-winged fly into a four-winged mutant, it was thought that evolutionary changes in Ubx regulation might explain the difference between insects that normally have four wings versus those that normally have two (Lewis, 1978). A comparison of Ubx expression in flies and butterflies (butterflies normally have four wings) revealed that in fact the difference does not seem to be at the level of Ubxregulation (Carroll et al., 1995), but instead at the level of genes downstream of Ubx (Weatherbee, 1998). Thus, despite their clear potential to alter body plans upon mutation in Drosophila, it has been difficult to document actual evolutionary changes in body plan that can be attributed to alterations in the initial boundaries of Hox gene expression . . . see more!

Germ line regeneration in Parhyale hawaiensis 

For certain animals such as sponges, cnidarians, flatworms, and colonial sea squirts, replacing a lost germline (the population of diploid cells that ultimately produces haploid gametes) is a simple corollary of total body plan regeneration (Bely and Nyberg 2009).  Many types of animals, however, lack such powers of regeneration and cannot replace a lost germline; examples include humans and the familiar research models CaenorhabditisDrosophilaXenopusDanio, and Mus (e.g., Barnes et al. 2006; Klein et al. 2010; Nieuwkoop and Sutasurya 1979; Sulston et al. 1983; Weidinger et al. 2003).

Research from our lab demonstrates the extraordinary ability of Parhyale hawaiensis, a marine amphipod crustacean, to replace its germline despite being incapable of total body plan regeneration . . . see more!

Structural Color in Butterflies

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The interactions of an organism with its ecological community are directly influenced by its appearance. An organism’s coloration can attract mates, warn others of a poisonous/venomous defense, serve as camouflage, or mimic other species. The insect order Lepidoptera (moths and butterflies) has long been recognized as an ideal group forinvestigating these interactions. With an estimated 140,000 species covering every continent except Antarctica, the Lepidopteran wing patterns represent one of the most thorough explorations of phenotypic space available to science. These patterns are produced by the mosaic juxtaposition of thousands of individually colored, derived hair cells known as scales… see more!

FUTURE DIRECTIONS

The main goal of my lab in the next few years will be to further our understanding of the developmental basis of evolutionary change. Some of this research will follow the same experimental lines as in the past. Studies in model systems, such as Drosophila, have identified genes that govern pattern formation during development. By isolating orthologs of these genes in other animals, and examining their expression patterns during development, we may be able to learn how developmental programs have been altered during evolution. These comparative studies will be primarily centered on arthropods, but where appropriate these investigations may be extended to annelids, mollusks, nematodes, and vertebrates as well. An increased focus, however, will be placed on an experimental analysis of the function of these genes in arthropods outside of Drosophila, and on an analysis of the molecular basis for evolutionary changes in gene expression patterns. We will focus on two animals, the grasshopper, Schistocercaamericana, and the amphipod crustacean, Parhyale hawaiensis, for the majority of these future studies … see more!