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RESEARCH |
My group focuses on molecular evolution; from the evolution of genes /gene families to using DNA markers to reconstruct evolutionary relationships among taxa. We use primarily neutral DNA markers for reconstructing molecular phylogenies or phylogeography. We are also interested in population level questions which mostly use mitochondrial and microsatellite DNA, however nuclear genes and introns have become increasingly useful.
There are a number of thrusts to my research. The first is to unravel evolutionary relationships among individuals and populations in order to tease out the different factors that shape current variability and differentiation. We examine the relative contributions of genetic drift, selection, demography and social structure. This allows one to examine how |
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variation is partitioned both temporally and geographically. Past population genetic projects investigated population structure, dispersal and gene flow, as well as examined the effects of habitat |
fragmentation on previously continuous populations. A major concern of this fragmentation is that these resulting small populations are more vulnerable to demographic changes and genetic drift, which could result in the loss of genetic diversity. Thus the results of many projects are applicable to conservation. Our past projects include studies on the endangered geometric tortoise, white and black rhinoceros, buffalo, wild cats, klipspringers, crocodiles, mole rats, pied babbler and petrels.
Another aspect of my research is the use of molecular markers to address sociality in eusocial insects and social mammals. For example, ants provide a good model for testing various predictions made by Hamilton's kin selection theory. Although there are numerous example mate-choice and kin selection in mammals, often the mechanism for this are not clearly elucidated in a |
| particular species studied. One approach is to explore the links with MHC (Major Histocompatibility Complex which is under balancing selection) and other effectors molecules, like olfactory and VNO (Vomeronasal Organ) receptors. However little is know about these two loci and how they have evolved, except that both gene families are characterised by massive gene duplication with many pseudo-genes. To investigate the molecular evolutions of these two gene families, we isolate and characterise these loci in non-model organisms and attempt to link the patterns of variation to selection, mate choice and kin selection. |
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| PUBLICATIONS |
* Papers by past/present students or postdoctoral fellows, whom I offer first authorship as a matter of policy. Student and postdoctoral names are in italics.
M. N. M. Techow, C. O'Ryan, R. A. Phillips, R. Gales, M. Marin, D. Patterson-Fraser, F. Quintana, M. S. Ritz, D. R. Thompson, R. M. Wanless and P. Ryan. 2009. Speciation and phylogeography of giant petrels Macronectes. Molecular Phylogenetics and Evolution, in press (Available online 13 September 2009).
J. M. Bishop, A. J. Leslie, S. L. Bourquin and C. O’Ryan. 2009. The declining effective population size on an overexploited top predator, Biological Conservation, 142(10): 2335 -2341.
M. N. M. Techow, P. Ryan and C. O'Ryan. 2009. Phylogeography and taxonomy of White-chinned and Spectacled Petrels. Molecular Phylogenetics and Evolution, 52: 25-33.
M. Melo and C. O’Ryan. 2007. Mitochondrial phylogeography and genetic structure of the grey parrot (Psittacus erithacus) reveals an independent history for the Príncipe Island population, Molecular Ecology, 16(8):1673-1685.
J. M. Bishop, C. O’Ryan and J. U. M Jarvis. 2007. Social common mole-rats enhance outbreeding via extra-pair mating, Biology Letters, 3:176-179.
E. H. Harley, I. Baumgarten, J. Cunningham and C. O’Ryan. 2005. Genetic variation and population structure in remnant populations of black rhinoceros, Diceros bicornis, in Africa, Molecular Ecology,14(10): 2981-2990.
Sebastián, C. R., Etheridge, S. M., Cook, P. A., O'Ryan, C. & Pitcher, G. C. 2005. Phylogenetic analysis of toxic Alexandrium (Dinophyceae) isolates from South Africa: implications for the global phylogeography of the Alexandrium tamarense species complex . Phycologia, 44: 49-60.
J. M. Bishop, J. U. M. Jarvis, A. C. Spinks, N. C. Bennett, C. O'Ryan. 2004. Molecular insight into patterns of colony composition and paternity in the common mole-rat Cryptomys hottentotus hottentotus. Molecular Ecology, 13( 5): 1217 – 1230.
N. M. S. M. Techow and C. O’Ryan. 2004. Characterisation of microsatellite loci in White-chinned Petrel (Procellaria aequinoctialis) and cross-amplification in six other procellariiform species. Molecular Ecology Notes, 4(1): 33 –35. |
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LAB MEMBERS |
| Past students |
N. Coutts, 2009, UCT
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Ph.D. Population dynamics and mate choice in the Southern White Rhinoceros (Cerathotherium simun simum): A genetic study using microsatellite and MHC loci. |
A. Manayas, 2009, UCT |
M.Sc. Population structure and paternity in South African live bearing sharks. |
N. Muna, 2008, UCT |
M.Sc. Investigation Of The Sociogenetic Structure Of The Endemic Fynbos Ant, Camponotus Klugii. |
L. Badenhorst, 2008, UCT |
M.Sc.The Characterisation Of MHC And The Population Structure Of Crocodiles. |
N. le Roex, 2008, UCT |
M.Sc. The Phylogeography Klipspringers in Southern Africa |
M. Techow, 2007, UCT |
Ph.D. Phylogeny and Phylogeography of Four Southern Ocean Petrels. |
C. Ruiz, 2005, UCT |
Ph.D. Phylogeny Of Dinoflagellates And The Development Of A DNA Diagnostic Test To Identify Harmful Algae Blooms |
Z. Van Helmond, 2004, UCT |
M.Sc. Initial Assessment Of Triplex PCR Assay: Application For Detection Of Toxic Dinoflagellates, Alexandrium Species (Dinophyceae), In Environmental Samples. |
P. Hedley, 2003,UCT |
M.Sc. Investigation Of Genetic Differentiation At Microsatellite And Major Histocompatibility Complex (MHC) Loci In South Africa |
B. Eick, 2003, UCT |
Ph.D. Population and Social Genetic Structure in Camponotus klugii and Molecular Phylogeny of Southern African Camponotus |
J. Cunningham, 2003, UCT |
Ph.D. Phlyogeography Tortoises And The Effects Of Habitat Fragmentation On The Endangered Geometric Tortoise, Psammobates Geometricus. |
J. Bishop. 2002. UCT |
Ph.D. The use of Microsatellite Markers to Determine Relatedness in Mole Rats. |
M. P. Melo, 2001, UCT |
M.Sc. Differentiation Between Principe Island And Mainland Populations Of The Grey Parrot (Psittacus erthacus) And The Implications For Their Conservation. |
A. Walker, 2000, UCT |
M.Sc. Hybridisation and Introgression in Helmeted Guinea Fowl (Numida meleagris) populations. |
J. Kelso, 2000, UCT |
M.Sc. The Impact of the Longline Fishing Industry on Whitechinned Petrels (Procellaria aequictialis). |
R. Wiseman, 1998, UCT |
M.Sc. The use of Eight Microsatellite Loci to Evaluate Genetic Introgression between the African Wild Cat (Felis lybica) and the Domestic Cat (Felis catus) |
R. Krug, 1997, UCT |
M.Sc. The Genetic Diversity In A Founded Population Of African Buffalo (Syncerus caffer): An Example Of An Artificial Bottleneck. |
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| COLLABORATIONS |
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Dr Jacqui Bishop, UCT Zoology |
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Prof. Maartin De Wit, AEON - Africa Earth Observatory Network, and Geology, UCT |
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Prof Allen Rodger, UCT, Chem |
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Dr Mandy Ridley, Percyfitzpatrick, UCT |
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Dr Gary Bronner, UCT, Zoo |
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Dr Alison Leslie, University of Stellenbosch |
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LINKS |
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