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Scott F Gilbert

Publications and source records attributed to Scott F Gilbert.

14 recordsLinked to original sources
PubMed2005

How the turtle forms its shell: a paracrine hypothesis of carapace formation.

We propose a two-step model for the evolutionary origin of the turtle shell. We show here that the carapacial ridge (CR) is critical for the entry of the ribs into the dorsal dermis. Moreover, we demonstrate that the maintenance of the CR and its ability to attract the migrating rib precursor cells depend upon fibroblast growth factor (FGF) signaling. Inhibitors of FGF allow the CR to degenerate, with the consequent migration of ribs along the ventral body wall. Beads containing FGF10 can rearrange rib migration in the chick, suggesting that the CR FGF10 plays an important role in attracting the rib rudiments. The co-ordinated growth of the carapacial plate and the ribs may be a positive feedback loop (similar to that of the limbs) caused by the induction of Fgf8 in the distal tips of the ribs by the FGF10-secreting mesenchyme of the CR. Once in the dermis, the ribs undergo endochrondral ossification. We provide evidence that the ribs act as signaling centers for the dermal ossification and that this ossification is due to bone morphogenetic proteins secreted by the rib. Thus, once the ribs are within the dermis, the ossification of the dermis is not difficult to achieve. This relatively rapid means of carapace formation would allow for the appearance of turtles in the fossil record without obvious intermediates.

Animals↗
PubMed2005

Mechanisms for the environmental regulation of gene expression: ecological aspects of animal development.

The environment can play a significant role in the production of phenotypes. However, the developmental mechanisms by which the environmental agents effect normal development are just becoming known. At least three paths have been found through which the environment can modify gene activity. The first is the neuroendocrine route. Here, the nervous system monitors the environment and transfers signals to the endocrine system. The endocrine hormones can then alter gene expression. The second route involves environmental factors that change the methylation pattern of genes, thereby altering their transcriptional capabilities. The third route involves the direct induction of gene expression in the host by microbial symbionts. The normal regulation of phenotype production by the environment should be considered a normal component of development and developmental biology.

Animals↗
PubMed2005

Putting evo-devo into focus. An interview with Scott F. Gilbert. Interview by Alexander T. Mikhailov.

This article announces Dr. Scott F. Gilbert as the winner of the Alexander Kowavelsky international prize (2004) and briefly reviews his achievements in developmental biology and evo-devo. Dr. Gilbert replies to the interviewer's questions concerning his personal interest in evo-devo and current controversies within the field. His thoughts and comments represent a unique blend of research talents and skills, curiosity and creativity.

Awards and Prizes↗
PubMed2004

Mechanisms for the environmental regulation of gene expression.

The environment can play a significant role in the production of phenotypes. However, the developmental mechanisms by which the environment can affect normal development are only now being elucidated. At least three paths have been found through which the environment can modify gene expression. The first is the neuroendocrine route, wherein the nervous system transmits signals from the environment to the endocrine system and the hormones alter gene expression. The second pathway involves environmental agents that change the methylation pattern of genes, thereby altering their transcriptional capacities. The third route involves the direct induction of gene expression in the host by its microbial symbionts. The normal environmental regulation of phenotype production should be considered a normal component of development and developmental biology.

Animals↗
PubMed2004

'Show me your original face before you were born': the convergence of public fetuses and sacred DNA.

Embryology is an intensely visual field, and it has provided the public with images of human embryos and fetuses. The responses to these images can be extremely powerful and personal, and the images (as well as our reactions to them) are conditioned by social and political agendas. The image of the 'autonomous fetus' abstracts the fetus from the mother, the womb, and from all social contexts, thereby emphasizing 'individuality'. The image of 'sacred DNA' emphasizes DNA as the unmoved mover, the eidos, the soul of the human being. Since fertilization involves the forming of a new constellation of DNA in the zygote, the act of fertilization is being perceived as the secular and technical equivalent of ensoulment. This privileges fertilization above the other possible scientifically valued times when 'human life' begins.

Beginning of Human Life↗
PubMed2003

T-box gene products are required for mesenchymal induction of epithelial branching in the embryonic mouse lung.

The regulation of signaling pathways is a prerequisite for coordinating the induction between mesenchymal and epithelial tissues during morphogenesis. Mesenchymal FGF10 is known to be an important paracrine factor regulating the branching morphogenesis of the bronchial epithelium. By using antisense oligonucleotides (AS ODNs) and in vitro culture of embryonic lungs, we demonstrate that the transcription factors Tbx4 and Tbx5 are critical for the expression of mesenchymal FGF10. Treatment of embryonic lung cultures with AS ODNs to Tbx4 and Tbx5 reduces the level of these transcripts, suppresses Fgf10 expression in the mesenchyme, and completely eliminates the formation of new lung branches. If FGF10 is locally replaced in these AS ODN-treated lungs, epithelial branching is restored. These studies provide evidence that the production of branching signals by the lung mesenchyme is mediated by T-box genes.

Animals↗
PubMed2003

Opening Darwin's black box: teaching evolution through developmental genetics.

When biologists are asked to discuss the evidence for evolution at public forums, they usually use well-established microevolutionary examples. Although these examples show the efficacy of evolution within species, they often leave audiences susceptable to the arguments of creationists who deny that evolution can create new structures and species. Recent studies from evolutionary developmental biology are beginning to provide case studies that specifically address these concerns. This perspective presents some of this new evidence and provides a framework in which to explain homology and phylogeny to such audiences.

Animals↗
PubMed2003

Educating for social responsibility: changing the syllabus of developmental biology.

Developmental biology is deeply embedded in the social issues of our times. Such topics as cloning, stems cells, reproductive technologies, sex selection, environmental hormone mimics and gene therapy all converge on developmental biology. It is therefore critical that developmental biologists learn about the possible social consequences of their work and of the possible molding of their discipline by social forces. We present two models for integrating social issues into the developmental biology curriculum. One model seeks to place discussions of social issues into the laboratory portion of the curriculum; the other model seeks to restructure the course, such that developmental biology and its social contexts are synthesized directly.

Curriculum↗
PubMed2003

The morphogenesis of evolutionary developmental biology.

The early studies of evolutionary developmental biology (Evo-Devo) come from several sources. Tributaries flowing into Evo-Devo came from such disciplines as embryology, developmental genetics, evolutionary biology, ecology, paleontology, systematics, medical embryology and mathematical modeling. This essay will trace one of the major pathways, that from evolutionary embryology to Evo-Devo and it will show the interactions of this pathway with two other sources of Evo-Devo: ecological developmental biology and medical developmental biology. Together, these three fields are forming a more inclusive evolutionary developmental biology that is revitalizing and providing answers to old and important questions involving the formation of biodiversity on Earth. The phenotype of Evo-Devo is limited by internal constraints on what could be known given the methods and equipment of the time and it has been framed by external factors that include both academic and global politics.

Animals↗
PubMed2002

Stephen J Gould.

Explore the source record for details and available documents.

Biological Evolution↗
PubMed2002

The genome in its ecological context: philosophical perspectives on interspecies epigenesis.

Epigenesis concerns the interactions through which the inherited potentials of the genome become actualized into an adult organism. In addition to epigenetic interactions occurring within the developing embryo, there are also critical epigenetic interactions occurring between the embryo and its environment. These interactions can determine the sex of the embryo, increase its fitness, or even be involved in the formation of particular organs. This essay will outline the history of environmental concerns in developmental biology and provide some reasons for the decline and resurgence of these ideas, and it will then focus on two areas that have recently gained much attention: predator-induced polyphenisms and developmental symbioses. Research in these two areas of interspecies cooperation in morphogenesis has profound implications for what we consider to be normal development and how we proceed to study it. Studies of predator-induced polyphenism have shown that soluble factors from predators can change the development of prey in specific ways. Prey has evolved mechanisms to sense compounds released from their predators and to use these chemical cues to change their development in ways that prevent predation. New techniques in molecular biology, especially polymerase chain reaction and microarray analysis, have shown that symbioses between embryos and bacteria are widespread and that animals may use bacterial cues to complete their development.

Animals↗
PubMed2002

From development to evolution: the re-establishment of the "Alexander Kowalevsky Medal".

The Saint Petersburg Society of Naturalists has reinstated the Alexander O. Kowalevsky Medal. This article announces the winners of the first medals and briefly reviews the achievements of A.O. Kowalevsky, the Russian comparative embryologist whose studies on amphioxus, tunicates and germ layer homologies pioneered evolutionary embryology and confirmed the evolutionary continuity between invertebrates and vertebrates. In re-establishing this international award, the Society is pleased to recognize both the present awardees and the memory of Kowalevsky, whose work pointed to that we now call evolutionary developmental biology.

Animals↗