Homology

'Homology' as a concept became increasingly elusive during the course of the 20th century. The central debates and controversies concern both fundamental definitions and the nature of the criteria by which homology is judged. Attempts to move away from comparative morphology to ideas based on developmental pathways have tended to founder on the fact that developmental pathways evolve and that similar cells or tissues or structures in animals will often have different developmental origins. The use of information about conserved molecules in seemingly conserved developmental processes has also proven controversial. In molecular biology, the use of the term 'homology' has given rise to more debate, although here the issue seems to involve primarily the criteria for assessing whether parts of genes are the same because of shared descent or for other reasons. The contributions to the book explore these topics systematically. There are chapters on the historical development of the concept of homology and its use in population studies. Other chapters deal with issues of homology in morphological and developmental studies, in behavioural studies, and especially in studies at the level of molecular genetics.

'Homology' as a concept became increasingly elusive during thecourse of the 20th century. The central debates and controversiesconcern both fundamental definitions and the nature of the criteriaby which homology is judged. Attempts to move away from comparativemorphology to ideas based on developmental pathways have tended tofounder on the fact that developmental pathways evolve and thatsimilar cells or tissues or structures in animals will often havedifferent developmental origins. The use of information aboutconserved molecules in seemingly conserved developmental processeshas also proven controversial.In molecular biology, the use of the term 'homology' has givenrise to more debate, although here the issue seems to involveprimarily the criteria for assessing whether parts of genes are thesame because of shared descent or for other reasons. Thecontributions to the book explore these topics systematically.There are chapters on the historical development of the concept ofhomology and its use in population studies. Other chapters dealwith issues of homology in morphological and developmental studiesin behavioural studies, and especially in studies at the level ofmolecular genetics.

Homology-History of a Concept (A. Panchen).Homoplasy, Homology and the Problem of 'Sameness' in Biology (D.Wake).Homology Among Divergent Paleozoic Tetrapod Clades (R.Carroll).Generation, Integration, Autonomy: Three Steps in the Evolution ofHomology (G. Müller & S. Newman).On the Homology of Structures and Hox Genes: The Vertebral Column(F. Galis).Developmental Basis of Limb Homology in Urodeles: HeterochronicEvidence from the Primitive Hynobiid Family (J. Hinchliffe & E.Vorobyeva).Larval Homologies and Radical Evolutionary Changes in EarlyDevelopment (R. Raff).A Research Programme for Testing the Biological Homology Concept(G. Wagner).Homology and Homoplasy: The Retention of Genetic Programmes (A.Meyer).Homology in the Nervous System: Of Characters, Embryology andLevels of Analysis (G. Striedter).Natural History and Behavioural Homology (H. Greene).Evolutionary Dissociations Between Homologous Genes and HomologousStructures (G. Wray).Establishing Homology Criteria for Regulatory Gene Networks:Prospects and Challenges (E. Abouheif).The Effect of Gene Duplication on Homology (P. Holland).Summary (B. Hall).Indexes.