REVIEW ARTICLE Cytomixis—a unique phenomenon in animal and plant Aninda Mandal & Animesh K. Datta & Sudha Gupta & Rita Paul & Aditi Saha & Benoy K. Ghosh & Arnab Bhattacharya & Mohsina Iqbal Received: 8 August 2012 / Accepted: 27 February 2013 # Springer-Verlag Wien 2013 Abstract Cytomixis is reported to be a uniform phenomenon in the context of fertilization during spermatogenesis of animals and in some lower groups of plants where oogamous reproduction prevails. However, the phenomenon is versatile in flowering taxa as it lacks uniformity in occurrences, causes, formation of intercellular bridges, involvement of number of cells in a cluster, evolutionary significance among others. A review on cytomixis is conducted with an objective that it may offer a scope to unravel some of the ambiguities associated with it and provide further information on cell, reproductive, structural and evolutionary biology. Keywords Spermatogenesis . Flowering plants . Chromatin migration . Intercellular bridges . Syncytium . Ambiguity Abbreviations AI Anaphase I CCs Cytoplasmic channels DMYPT Drosophila melanogaster myosin binding subunit of myosin phosphatase EM Electron microscope IBs Intercellular bridges MI Metaphase I PMCs Pollen mother cells RBM44 RNA binding motif protein 44 TEX14 Testis-expressed gene 14 Introduction Körnicke (1901) first studied cytomixis in microsporogenesis of Crocus sativus and Gates (1911) defined the phenomenon in Oenothera gigas as the process of extrusion of chromatin from the nucleus of one PMC into the cytoplasm of the adjacent mother cell. Omara (1976) considered cytomixis to be a spontaneous process occurring through the formation of cytoplasmic bridges between adjacent PMCs. Cell-to-cell contact in cytomixis achieved through cellular bridging pro- vided direct routes for transfer of signals and components, thereby allowing evolution of complex forms in multicellular organisms (Zani and Edelman 2010; Haglund et al. 2011). Haglund et al. (2011) suggested that the role of incom- plete cytokinesis, in certain tissues and developmental stages, give rise to cells interconnected in syncytia by stable intercellular bridges and it occurs in both female and male germ lines in species ranging from insects to humans as well as in some somatic tissues in invertebrates. Plasmodesmata in plants and the septal pore in fungi also represent intercellular bridges formed by incomplete cytokinesis (Robinson and Cooley 1996;Lůcas and Wolf 1993). Handling Editor: Alexander Schulz A. Mandal : A. K. Datta (*) : B. K. Ghosh : A. Bhattacharya Department of Botany, Cytogenetics, Genetics and Plant Breeding Section, University of Kalyani, Kalyani 741235 West Bengal, India e-mail: dattaanimesh@gmail.com S. Gupta Department of Botany, Pteridology–Palaeobotany Section, University of Kalyani, Kalyani 741235 West Bengal, India R. Paul Department of Botany, Charuchandra College, Calcutta 700029, India A. Saha Department of Botany, Narasinha Dutt College, Howrah 711101, India M. Iqbal Department of Botany, New Alipore College, Calcutta 700053, India Protoplasma DOI 10.1007/s00709-013-0493-z