Rama Shankar Singh, Ph.D.
Telephone: (905) 525-9140
Office: LSB-531 Ext 24378
Lab: LSB-523 Ext 27413
Evolutionary genetics: molecular genetics of speciation in Drosophila; evolution of sex- and reproduction-related genes; evolution of human diversity and social systems (e.g., the Indian Caste System).
- Morton, R.A., Stone, J.R., Singh, R.S. 2013. Mate choice and the origin of menopause. PLoS Computational Biology. 9: e1003092.
- Singh, R.S. 2011. Darwin’s legacy: why biology is not physics: or why evolution has not become a common sense. Genome. 54:868-73.
- Jagadeeshan, S., Haerty, W., and R.S. Singh. 2011. Is speciation accompanied by rapid evolution? Insights from comparing reproductive and nonreproductive transcriptomes in Drosophila. International Journal of Evolutionary Biology. 2011:595121.
- Ahuja, A., De Vito, S., and R.S. Singh. 2011. Condition dependence and the nature of genetic variation for male sex comb bristle number in Drosophila melanogaster. Genetica. 139:505-510.
- Artieri, C.G., and R.S. Singh. 2010. Molecular evidence for increased regulatory conservation during metamorphosis, and against deleterious cascading effects of hybrid breakdown in Drosophila. BMC Biology. 8:26.
- Singh, R.S., and Artieri, C.G. 2010. Male sex drive and the maintenance of sex: evidence from Drosophila. Journal of Heredity. Suppl 1:S100-6.
- Artieri, C.G., and R.S. Singh. 2010. Demystifying phenotypes: The comparative genomics of evo-devo. Fly (Austin). 4:18-20.
- Artieri, C. G., W.Haerty and R.S. Singh. 2009. Ontogeny and phylogeny: molecular signatures of selection, constraint, and temporal pleiotropy in the development of Drosophila. BMC Biology 7:42
- Kulathinal, R.J., and R.S. Singh. 2008. The molecular basis of speciation: from patterns to processes, rules to mechanisms (Invited Perspective to mark Darwins Centennial). Journal of Genetics 87:327-338.
- Singh, R.S. 2008. Women and Social Change: A New Gandhian Social Movement – Mahila Shanti Sena. Intl. Encyclopedia of Peace (in press)
- Haerty W, Artieri C, Khezri N, Singh RS, Gupta BP. 2008. Comparative analysis of function and interaction of transcription factors in nematodes: extensive conservation of orthology coupled to rapid sequence evolution. BMC Genomics 9:399.
- Ahuja, A., and R.S. Singh. 2008. Variation and evolution of sex combs in Drosophila: Nature os selection response and theories of genetic variation for sexual traits. Genetics 179: 503-509.
- Artieri, C., W. Haerty, B. Gupta, and R.S. Singh. 2008. Sexual selection and maintenance of of sex: Evidence from comparisons of genomic accumulation of mutations and divergence of sex-related genes in sexual and hermaphroditic species od Caenorhabditis. Mol Biol Evol 25:972-979.
- Artieri, C.G., Haerty, W., Singh, R.S. 2007. Association Between Levels of Coding Sequence Divergence and Gene Misregulation in Drosophila Male Hybrids. Journal of Molecular Evolution 65: 697-704.
- Haerty, W., Jagadeeshan, S., Kulathinal, R.J., Wong, A., Ravi Ram, K., Sirot, L.K., Levesque, L., Artieri , C.G., Wolfner, M.F., Civetta, A., Singh, R.S. 2007. Evolution in the fast lane: Rapidly evolving sex-related genes in Drosophila. Genetics 177: 1321-1335.
- Drosophila 12 Genome Consortium (including W. Haerty, C. Artieri, S. Jagadeeshan and R. Singh). 2007. Evplution of genes and genomes on the Drosophila phylogeny. Nature 450: 203-218.
- Jagadeeshan S. and Singh R.S. 2007. Rapid evolution of outer egg membrane proteins in the Drosophila melanogaster subgroup: a case of ecologically driven evolution of female reproductive traits. Mol Biol Evol 24: 929-938.
- Haerty W. and Singh R.S. 2006. Gene Regulation Divergence Is a Major Contributor to the Evolution of Dobzhansky-Muller Incompatibilities between Species of Drosophila. Mol Biol Evol 23: 1707-1714
- Jagadeeshan S. and Singh R.S. 2006. A time-sequence functional analysis of mating behaviour and genital coupling in Drosophila: role of cryptic female choice and male sex-drive in the evolution of male genitalia. J Evol Biol 19: 1058-1070
- Torgerson, D.G., and Singh, R.S. 2006. Enhanced adaptive evolution of sperm-expressed genes on the mammalian X chromosome. Heredity 96(1): 39-44.
- Musters, H., Huntley, M.A., and Singh.R.S. 2006. A Genomic Comparison of Faster-Sex, Faster-X, and Faster-Male Evolution between Drosophila melanogaster and Drosophila pseudoobscura. J. Mol. Evol. 61(5): 650-658
- Torgerson, D.G., Whitty, B.R., and Singh, R.S. 2005. Sex-specific functional specialization and the evolutionary rates of essential fertility genes. J. Mol. Evol. 61(5): 650-658.
- Jagadeeshan, S., and Singh, R.S. 2005. Rapidly Evolving Genes ofDrosophila: Differing levels of Selective Pressure in Testis, Ovary and Head Tissues Between Sibling Species. Mol Biol Evol. 22: 1793 1801.
- Singh, R.S., and Kulathinal, R.J. 2005. Male sex-drive and masculinization of the genome. BioEssays 27: 518-25.
- Singh, R.S. 2001. The Indian Caste System, human diversity and genetic determinism. In Thinking about evolution: Historical, philosophical and political perspectives. R.S. Singh et al. (eds.), Cambridge University Press.
- Singh, R.S. 2001. Polymorphisms. Encyclopedia of Genetics. Academic Press, New York.
- Singh, R.S. and R.J. Kulathinal. 2000. Sex gene pool evolution and speciation: A new paradigm. Genes Genet. Syst. 75: 119-130.
- Kulathinal, R.J. and R.S. Singh. 2000. Gene flow between D. pseudoobscura and D. persimilis?: A reply to Noor, Johnson and Hey.Evolution 54: 2176-2177.
- Kulathinal, RJ. and R.S. Singh. 2000. A biogeographic genetic approach for testing the role of reinforcement: The case of Drosophila pseudoobscura and D. persimilis. Evolution 54(1): 210-217.
- Singh, R.S. 2000. Toward a unified theory of speciation. In Evolutionary genetics: From molecules to morphology. R.S. Singh and C.B. Krimbas (eds.), Cambridge University Press.
- Singh, R.S., W.F. Eanes, D.A. Hickey, L.M. King and M.A. Riley. 2000. The molecular foundations of population genetics. In Evolutionary genetics: From molecules to morphology. R.S. Singh and C.B. Krimbas (eds.), Cambridge University Press.
- Singh, R.S., S.M. Singh and R.S. Pandeya. 1999. Genetic Resources, Biotechnology, and World Food Supply: A Special Symposium. Genome42: 551-655.
- Civetta, A. and R.S. Singh. 1999. Broad-sense of sexual selection, sex gene pool evolution and speciation. Genome 42: 1033-1042.
- Kulathinal, R. and R.S. Singh. 1998. Cytological characterization of premeiotic versus postmeiotic defects producing hybrid male sterility among sibling species of the Drosophila melanogaster complex. Evolution52: 1067-1079.
- Civetta, A. and R.S. Singh. 1998. Sex and speciation: Genetic architecture and evolutionary potential of sexual versus nonsexual traits in the sibling species of the Drosophila melanogaster complex. Evolution 52: 1080-1092.
- Civetta, A. and R.S. Singh. 1998. Sex-related genes, directional sexual selection and speication. Mol. Biol. Evol. 15: 901-909.
- Bromfield, E.S.P., A.M.P. Behara, R.S. Singh and L.R. Barran. 1998. Genetic variation in local populations of Rhizobium meliloti. Soil Biol. and Biochem.30: 1707-1716.
- Joly, D. and R.S. Singh. 1997. Genetic basis of sperm and testis length differences and epistatic effect on hybrid inviability and sperm motility between Drosophila simulans and D. sechellia. Heredity 78: 354-362.
- Civetta, A. and R.S. Singh. 1995. High divergence of reproductive tract proteins and their association with postzygotic reproductive isolation in Drosophila melanogaster and Drosophila virilis group species. J. Mol. Evol. 41: 1085-1095.
- Long, A.D. and R.S. Singh. 1995. Molecules versus morphology: The detection of selection acting on morphological characters along a cline in Drosophila melanogaster. Heredity 74: 569-581.
- Zeng, L.-W. and R.S. Singh. 1995. A general method for identifying major hybrid male sterility genes in Drosophila. Heredity 75: 331-341.
- Singh, R.S. and L.-W. Zeng. 1994. Genetic divergence, reproductive isolation and speciation. In: Non-Neutral Evolution Theories and Data. G.B. Golding (ed.), pp. 217-232, Chapman and Hall, N.Y.
- Zeng, L.-W. and R.S. Singh. 1993. A combined classical genetic and high resolution two-dimensional electrophoretic approach to the assessment of the number of genes affecting hybrid male sterility in Drosophila simulans and Drosophila sechellia. Genetics 135: 135-147.
- Stoehr, M.U. and R.S. Singh. 1993. Restriction map and polymophisms of nuclear ribosomal genes of Populus balsamifera. Tree Physiology 12: 419-425.
- Zeng, L.-W. and R.S. Singh. 1993. The genetic basis of Haldane’s Rule and the nature of asymmetric hybrid male sterility between Drosophila simulans, D. mauritiana and D. sechellia. Genetics 134: 251-260.
- Singh, R.S. and A.D. Long. 1992. Geographic variation in Drosophila: From molecules to morphology and back. Trends in Ecology and Evolution7: 340-345.
- Choudhary, M., M.B. Coulthart and R.S. Singh. 1992. A comprehensive study of genic variation in natural populations of Drosophila melanogaster. VI. Patterns and processes of genic divergence between D. melanogaster and its siblings species D. simulans. Genetics 130: 843-853.
- Singh, R.S., C.B. Krimbas, D. Paul and J. Beatty (editors). 2001. Thinking about evolution: Historical, philosophical and political perspectives. Cambridge University Press, Cambridge.
- Singh, R.S. and C. Krimbas (editors). 2000. Evolutionary genetics: From molecules to morphology. Cambridge University Press, Cambridge.
Origin and evolution of sex differences
Sex and Sexual dimorphism constitute the two most spectacular aspects of organismic diversity. Darwin invented his theory of sexual selection through female choice to explain certain secondary sexual traits in the male that on the surface looked maladaptive and hence could not be explained by natural selection. Sexual selection has gained considerable interest, especially of behavioral biologists, but it has always remained as a secondary in evolutionary biology. Advances in functional and evolutionary genomics provide opportunities to investigate the origin and evolution of sex, sexual dimorphism, sexual selection and speciation – at an unprecedented scale. Our lab is involved in a variety of projects integrating behavioral, morphological, developmental and genomic/transcriptomic data to investigate important evolutionary problems related to sex.
Human sexual system and the evolution of sex specific traits in humans– a computational approach. A current theme of interest is how sexual selection , particularly mate choice, has impacted the evolution of sex specific traits. We use a variety of Bioinformatics approaches to study topics under this theme. For instance, using simulations, we have recently shown that mate choice, particularly the preference of men to mate with younger women may have played an important role in the evolution of menopause. Similarly male mate choice may have also been important in the evolution of aging patterns and the evolution of sex specific disorders and diseases. We are interested in comparing patterns of divergences between tissue-specific genes in humans and chimps to uncover trends and patterns that may explain the evolutionary origins of sex-specific traits in humans (including disease patterns).
- Computational analyses of structural and regulatory evolution of tissue specific genes in humans and the great apes.
- Evolutionary genomic/transcriptomics of sexual dimorphisms in human health
Evolution and development: The Sex Comb of Drosophila
The male sex combs of Drosophila, an array of specialized bristles present only on the male’s foreleg, exhibit remarkable morphological variation within and between species. Bristle number has been shown previously to have varying effects on female preferences in different species, making these a model trait for studies of sexual trait diversification and their role in reproductive isolation. Two replicates of D. melanogaster lines divergent for sex comb bristle number have been developed through long term artificial selection. These lines allow us not only to test molecular signatures of artificial selection, but also to understand how developmental pathways respond to such selective pressures.
- Expression profiles of genes involved in the development of the sex comb
Rapidly evolving sexual systems and the genomics of speciation
An important goal in evolutionary biology has been to elucidate the molecular basis of species formation. Patterns of divergence between closely related species suggest there may be a particular functional class of genes that is preferentially involved in speciation. For example, the pronounced effects of reproductive traits manifested in hybrid incompatibilities are well-known. In addition, reproductive characters have been shown to exhibit rapid divergence within species through sexual selection. Over the last twenty years, our laboratory has been involved in the molecular characterization of rapidly evolving sex and reproduction related (SRR) genes in Drosophila male and female reproductive systems, and have investigated how these relate to hybrid sterility and reproductive isolation. More recently we have adopted a functional genomics approach to resolve the problem of sex and speciation using a variety of model organisms.
- Rapid divergence of sex and reproduction-related (SRR) genes
- Gene expression, gene networks and hybrid sterility
Sexual selection and evolution of Life history traits
Mating systems (mate choice, mating strategies) not only shape the nature of selection in populations but also influence the evolution of sex specific characters. Darwin noted that males, with their ‘superior strength, pugnacity, song and dance’ are almost always the initiators of sexual interactions. Males have evolved a variety of reproductive strategies to secure multiple mating and increase their fitness – even if some of these strategies may harm females. Males may play an important role in ‘driving’ the sexual system, which have important consequences; such as how females respond to male behaviours, the rapid evolution of male-specific traits (behaviour, morphology and molecules). We are investigating the evolution of male life history traits and their impact on the evolution of sexually dimorphic traits.
- Evolution of male specific sex and reproduction related traits (morphology)
- The interrelationship between evolution of sex-specific life histories, sexual selection, and the evolution of sexually dimorphic traits.
- Genomic signatures of Male driven sexual selection