Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học Journal of Biology đề tài: Comparative embryology without a microscope: using genomic approaches to understand the evolution of development. | Journal of Biology Minireview Comparative embryology without a microscope using genomic approaches to understand the evolution of development David A Garfield and Gregory A Wray Address Biology Department and Institute for Genome Science Policy Duke University Durham NC 27708 USA. Correspondence David Garfield. Email dag23@. Gregory Wray. Email gwray@ Abstract Until recently understanding developmental conservation and change has relied on embryological comparisons and analyses of single genes. Several studies including one recently published in BMC Biology have now taken a genomic approach to this classical problem providing insights into how selection operates differentially across the life cycle. It is an idea as old as the study of development itself embryos of different species are more similar during earlier stages than later ones 1 . The first detailed descriptions came from Karl Ernst von Baer whose meticulous observations of vertebrate embryos invented the field of developmental biology. Although von Baer s eponymous law stating that early development is more conserved than later development was formulated without an explicit evolutionary context Charles Darwin considered embryological similarity to be one of the most powerful forms of evidence for common descent when he wrote the Origin of Species. During the 150 years that have passed since that momentous publication embryologists have uncovered numerous exceptions to von Baer s generalization 2 . Yet it remains true that early development is often remarkably conserved among even distantly related species. Exactly why this should be so remains unclear. Alternative views of developmental constraint One view is that developmental similarity is the result of functional constraint and thus maintained by negative selection. The basic idea is that the processes of early development influence many later processes so functional changes in genes underlying early development will generally be .
