Only a few years ago, Developmental Dynamics published work focused almost exclusively on vertebrate development. In recognition of the enormous contributions that have come from genetic studies in model organisms such as Drosophila and Caenorhabditis elegans, the Journal began a successful push in 2003 to attract more papers using invertebrate systems. The publication of this special issue, containing a collection of 22 reviews and one original research article focused on diverse and interesting topics in C. elegans biology, is the latest result of this continued effort.

Over the past 3 decades, C. elegans has been one of most popular model organisms to study development, primarily due to its powerful forward genetics. Analyses of worm mutants with various defects have had a huge impact on our understanding of the diverse mechanisms of spatial and temporal regulation during development. Studies of worm genes have not only uncovered the roles of many cell signaling and regulatory pathways in cell differentiation and developmental pattern formation, but have also made invaluable contributions to the construction of these conserved pathways by discovering key factors and determining the functional relationships between the factors. Many genes discovered in worms have become the founding members of genes families with important and evolutionarily conserved regulatory functions. Indeed, over the past decade, genetics studies in C. elegans have resulted in three Nobel prizes for groundbreaking discoveries of some of the most important paradigms in biology, such as programmed cell death (apoptosis), double-stranded RNA-mediated interference (RNAi), and the use of the green fluorescent protein. Other findings, such as the discovery of microRNA-mediated gene silencing, have also tremendously impacted biological sciences.

In the 1990s, the popularity of C. elegans climbed sharply, as indicated by the increase in the number of publications per year (Fig. 1) and the large number of attendees at the biannual international C. elegans meeting. In the late 1990s, there were even worries that the field might be close to saturation. However, over the past decade we have seen continued growth, albeit with a rate slower than that of 1990s (Fig. 1). The current high level of productivity of the field may be attributed to multiple factors, including two worth mentioning here. First, while many C. elegans laboratories continue to tackle fundamental developmental biology problems (examples are described in several excellent reviews in this issue), studies have expanded to include a wider range of biological processes, many of which may not be regarded as developmental biology by a narrowly defined criterion. For example, C. elegans has become a powerful system for studying many basic cell biology problems, and a popular model for analyzing animal responses to environmental changes (such as nutrient conditions, pathogen infections, and various stresses), all of which are closely related to the problems of aging and human diseases. Several thoughtful review articles in this issue summarize the exciting new research results in these areas. In addition, tackling metabolic problems, including lipid function and homeostasis, has become a trend in the worm field. We get a glimpse at the progress made in this area from one of the reviews in this issue.

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Figure 1. Number of research publications using Caenorhabditis elegans as a model organism by year since 1974. Thirteen and 744 research articles were published in 1974 and 2009, respectively. Data taken from WormBase release WS210. [Color figure can be viewed in the online issue, which is available at]

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Second, C. elegans has become more popular because it is now much more approachable for “casual” worm researchers, thanks in part to the advancement of technology as well as the wonderful tools developed by some more experienced worm laboratories. Unlike 10 or 15 years ago, when studies using C. elegans were almost exclusively done by scientists who had gone through rigorous training with this organism, today's students can often obtain mutants of their favorite genes by ordering the deletion mutants from the Gene Knockout Consortium, or by simply examining the phenotypes after applying the “ultra-easy” feeding RNAi procedure. The establishment of C. elegans laboratories at almost all major research institutions has also facilitated inclusion of the organism as a viable system for many nonworm laboratories. These days, if you identify an interesting mammalian gene through human genetics or other methods, it would almost be “silly” not to take a look at the mutant of the worm homolog, if there is one. Indeed, many laboratories have developed worm research projects based on studies on human disease genes, examples of which can be found in some of the reviews in this issue.

We have good reason to believe that the C. elegans research community will continue to be productive and make important contributions to our understanding of many aspects of animal biology in the next decade. New research themes and directions will likely continue to surface, and the vitality of this research community is palpable from the depth and breadth of the many excellent reviews included in this issue of Developmental Dynamics. We are also likely to see an increase in studies using both the worm and other model systems, reflected by nonworm laboratories doing worm genetics and by the usage of other systems, such as mouse genetics, in some traditional worm laboratories. The decade ahead will continue to be an exciting time for all biological scientists who breed worms in their research.

I thank Kimberly Van Auken at WormBase for preparing Figure 1.