Reviews & Analysis

Evo–devo is now a mature field encompassing a wide range of research areas. The author offers his assessment of its main theoretical implications and challenges for the immediate future.

Evo–devo has its origins in both palaentology and developmental genetics, but there is a tendency to overlook the former as being old-fashioned. However, integrating information from both sources is essential to generating realistic hypotheses about how developmental processes evolved.

Genetic studies in mice are providing an increasingly complete picture of the signalling interactions that underlie the development of the mammary gland; in the process they inform us about the human disorders that are caused by mutations in these pathways, including breast cancer.

Remarkably, conservation of genomes of all species in terms of sequence and synteny is accompanied by a great diversity of karyotypes, which can be explained by rearrangements of chromosomal segments. The authors look at how these rearrangements come about, and how their analysis can construct evolutionary relationships among mammals.

The genomics era offers many exciting opportunities to answer questions in evo–devo. Newly sequenced genomes of phylogenetically diverse organisms allow us to chronicle the gain and loss of morphological features and correlate them with their genetic underpinnings.

A module is a linked group of phenotypic traits that depend on each other but are relatively independent of other modules. The insight that developmental mechanisms are modular is important for their evolution, making modularity a key concept in evo–devo and beyond.

Transposable elements are diverse and abundantly present in eukaryotic genomes. To help with the challenge of their identification and annotation, these authors propose the first unified hierarchical classification system for transposable elements. The system and nomenclature are kept up to date in a related database — WikiPoson.

Functions of histone lysine demethylases in a range of developmental and physiological processes are rapidly being uncovered, as are the roles of these enzymes in disease. Histone demethylases also provide a promising new route towards the therapeutic targeting of epigenetic regulators.

Eukaryotes have evolved small RNA-guided regulatory networks to control RNA transcripts, chromatin, repeated genomic sequences and invasive agents, such as viruses. Spatiotemporal regulation of the transcriptome through these pathways has shaped the evolution of eukaryotic genomes and contributed to the complexity of multicellular organisms.

Identifying regions of the human genome that have been subject to selection is key to understanding our evolution, and provides insights into the genetic basis of disease. However, important caveats require consideration when interpreting the results of attempts to identify selected regions.

Although the early years of genetics have been well described by historians, it is only now being realized that this was one of the earliest emerging disciplines in twentieth-century biology to benefit from the contributions of women. Many, however, became 'silent scientists' — publishing no paper beyond their dissertation.

Recent studies in yeast, invertebrates and mammals have begun to solve the puzzle of how dietary restriction results in increased longevity. An increased knowledge of the underlying pathways promises to provide new directions for treating ageing-related diseases in humans.

Advances in technology and improved genome annotation have greatly clarified the role of genome architecture in the aetiology of many well-known and newly described clinical disorders. The authors focus on a group of genomic disorders mediated by segmental duplications to illustrate recent advances in their dissection and diagnosis.

A combination of ecological, population genetic and molecular studies has stimulated progress in understanding the forces that shape natural phenotypic variation. Technical advances that allow fitness differences to be linked to individual polymorphisms now promise rapid progress in this field.

Prompted by the identification of the gene that is mutated in the last assigned Fanconi anaemia (FA) complementation group, the author discusses the growing evidence that FA proteins function as signal transducers and DNA-processing molecules in a DNA-damage response network, which consists of many proteins that maintain genome integrity.

Defects in kidney development can cause a wide range of disease phenotypes, from obvious renal abnormalities and Wilms tumour to hypertension and cardiovascular disease. A detailed understanding of the developmental genetics of the kidney is key to combating these diseases.

Gene conversion — the unidirectional transfer of information between highly homologous sequences — influences genome evolution and is the cause of several human inherited disorders. This article reviews our understanding of the mechanism of gene conversion, and its consequences for human health.

Recent findings suggest that RNA-based elements such as ribozymes and RNA sensors have a widespread role in gene expression regulation. Studies of these RNAs provide insights into mechanisms of gene expression control and the evolution of cellular functions from RNA-based origins.

Integrating physical and genetic interaction data is essential if we are to fully understand cellular networks. The classification of interactions beyond the simple physical versus genetic divide promises to accelerate progress, as illustrated by recent successes in network integration.

The authors argue that a new approach, the functional synthesis, which combines evolutionary analyses of gene sequences with molecular biology experiments, opens new avenues to the study of the evolution of gene function and provides answers to some long-standing questions about evolutionary processes.