Keywords
Genetic diversity
Population structure
Vigna unguiculata
How to Cite
Abstract
Enzyme electrophoresis was used to estimate the genetic diversity and population structure of thirteen Vigna unguiculata ssp. unguiculata var. spontanea populations in Sudan. Plant genotypes were homozygous at most loci and at several populations. Nine of the twenty-one allozyme loci analysed (42.9%) showed detectable polymorphism, but only 11.4% of loci were polymorphic within local populations. Gene diversity at the species level and at the population level was low (Hes = 0.084; Hep = 0.049, respectively). Analysis of fixation indices, calculated for all polymorphic loci in each population showed a substantial deficit of heterozygotes relative to Hardy – Weinberg expectations. This deficit is partly associated with inbreeding due to self and consanguineous mating. High inbreeding and strong genetic differentiation coefficients were found. Allele frequency data revealed a low degree of within population genetic diversity (Hs = 0.049) and a high degree of genetic heterogeneity among populations (Gst = 0.409). The indirect estimates of gene flow were calculated based on the level of genetic differentiation between populations and frequencies of private alleles. These were 0.274 and 0.043 respectively. Genetic and geographic distances were positively correlated although not significant, indicating that very little genetic variation is explained by difference in geographic pattern. This may be a result of inbreeding and genetic drift through a few founders coupled with limited pollen flow
References
Allard RW, Jain SK and Workman PL. 1968. The genetics of inbreeding populations. Adv Genet.,14:55-131.
Ba FS, Pasquet RS and Gepts P. 2004. Genetic diversity in cowpea [Vigna unguiculata (L.) Walp.] as revealed by RAPD markers. Genet Res Crop Evol., 51:539-550.
Barrett SCH and Kohn JR. 1991. Genetic and evolutionary consequences of small population size in plants: implications for conservation. In„Genetics and conservation of rare plants‟. Edited by Falk DA and Holsinger KE: Oxford University Press 3-30.
Barton NH and Slatkin M. 1986. A quasiequilibrium theory of the distribution of rare alleles in a subdivided population. Heredity 56:409-415.
Bi IZ, Maquet A and Baudoin JP. 2003. Population genetic structure of wild Phaseolus lunatus (Fabaceae), with special reference to population sizes. Am J Bot., 90:897-904.
Brown AHD and Allard RW. 1970. Estimation of the mating system in open-pollinated maize populations using isozyme polymorphism. Genetics 66:133-145.
Brown AHD. 1979. Enzyme polymorphism in plant populations. Theor Biol., 15:1-42.
Brown AHD. 1978. Isozymes, plant population genetic structure and genetic conservation. Theor Appl Genet., 52:145-157.
Chakraborty R, Fuerst PA and Nei M. 1978. Statistical studies on protein polymorphisms in natural populations. II. Gene differentiation between populations. Genetics 88:367-390.
Coulibaly S, Pasquet RS, Papa R and Gepts P. 2002. AFLP analysis of the phenetic organization and genetic diversity of Vigna unguiculata L. Walp. reveals extensive gene flow between wild and domesticated types. Theor Appl Genet. 104:358-366.
Crow JF and Felsenstein J. 1968. The effect of assortative mating on the genetic composition of a population. Eugen Q. 15:85-97.
Feleke Y, Pasquet RS and Gepts P. 2006. Development of PCR-based chloroplast DNA markers to assess gene flow between wild and domesticated cowpea (Vigna unguiculata). Plant Syst Evol., 262:75-87.
Fery RL. 1985. The genetics of cowpea: a review of the world literature. In „Cowpea‟. Edited by Singh SR and Rachie KO John Wiley & sons, Chichester 25-62.
Frankel OH. 1974. Genetic conservation: our evolutionary responsibility. Genetics 78:53-65.
Gottlieb LD. 1981. Electrophoretic evidence and plant populations. Prog. Phytochem., 7:1-46.
Goudet J. 1995. FSTAT Version 1.2. A computer program to calculate F-statistics. J Heredity 86:485-486.
Hamrick JL. 1989. Isozymes and the Analysis of Genetic Structure in Plant Population. In „Isozymes in plant biology‟ Edited by Soltis, DE and Soltis PS Dioscorides press 9999 SW Wilshire Portland, Oregon 97225 87-105.
Hamrick JL. 1994. Genetic diversity and conservation in tropical forests. In „Proceedings of the International Symposium on Genetic Conservation and Production of Tropical Forest Tree Seed‟. Edited by Drysdale RM, John SET and Yapa AC. ASEAN-Canada Forest Tree Seed Center Project, Muak-Lek, Saraburi, Thailand. 1-9.
Hamrick JL and Godt MJ. 1990. Allozyme diversity in plant species. In „Plant population genetics, breeding and genetic resources„. Edited by Brown ADH, Clegg MT, Kahler AL and Weir BS.Sinauer, Sunderland, Massachusetts, USA. 43-63.
Hamrick JL and Godt MJW. 1996. Effects of life history traits on genetic diversity in plant species. Philos Trans. R. Soc. Lond. Biol. Sci., 351:1291-1298.
Hamrick JL, Godt MJW, Murawski DA, and Loveless MD. 1991. Correlations between species traits and allozyme diversity: implications for conservation biology. In „Genetics and Conservation of Rare Plants‟ Edited by Falk DA
and Holsinger KE. Oxford University Press, NY. 75-86.
Hardy O, Dubois S, Bi IZ and Baudoin JP. 1997. Gene dispersal and its consequences on the genetic structure of wild populations of Lima bean (Phaseolus lunatus) in Costa Rica. Plant Genet Res Newsletter 109:1-6.
Hedrick PW, Ginevan ME and Ewing EP. 1976. Genetic polymorphism in heterogeneous environments. Ann. Rev. Ecol. Syst., 7:1-32.
Kouadio D, Echikh N, Toussaint A, Pasquet RS and Baudoin JP. 2007. Organisation du pool génique de Vigna unguiculata (L.) Walp.: croisements entre les formes sauvages et cultivées du niébé. Biotechnol Agron Soc Environ., 11:47-57.
Levin DA and Kerster HW. 1971. Neighborhood structure in Plants diverse reproductive methods.Am. Nat., 105:345-352.
Levin DA and Kerster HW. 1974. Gene flow in seed plants. Evol. Biol., 22:130-139.
Li CC and Horvitz DG. 1953. Some methods of estimating the inbreeding coefficient. Am J Hum Genet., 5:107-117.
Loveless MD and Hamrick JL. 1984. Ecological determinants of genetic structure in plant populations. Ann Rev Ecol Syst 15:65-95.
Lush WM. 1979. Floral morphology of wild and cultivated cowpeas. Econ Bot., 33:442-447.
Marshall DR. 1990. Crop genetic resources: current and emerging issues. In „Plant population genetics, breeding, and genetic resources „. Edited by Brown AHD, Clegg MT, Kalher AL and Weir BS. Sinauer Associates, Sunderland, Massachusetts, USA. 367-388
Mayr E. 1963. Animal species and Evolution. Harvard University Press 797.
Nei M. 1972. Genetic distance between populations. Am. Nat., 106:282-292.
Nei M. 1973. Analysis of gene diversity in subdivided populations. Proc. Natl. Acad. Sci., 70:3321-3323.
Nei M. 1977. F-statistics and analysis of gene diversity in subdivided populations. Annals Hum Genet 41:225-233.
Panella L and Gepts P. 1992. Genetic relationships within Vigna unguiculata (L.) Walps. based on isozyme analysis. Genet Res Crop Evol 39:71-88.
Pasquet RS. 1993. Variation at isozyme loci in wild vigna unguiculata (L.) Walp.(Fabaceae, Phaseoleae). Plant Syst Evol., 186:157-173.
Pasquet RS. 1997. A new subspecies of Vigna zmngiriculata (Leguminosae-Papilionoideae). Kew Bull 52:840.
Pasquet RS. 1999. Genetic relationships among subspecies of Vigna unguiculata (L.) Walp. Based on allozyme variation. Theor Appl Genet., 98:1104-1119.
Pasquet RS, Schwedes S and Gepts P. 1999. Isozyme diversity in bambara groundnut. Crop Sci., 39:1228-1236.
Pasquet RS, Peltier A, Hufford MB, Oudin E, Saulnier J, Paul L, Knudsen JT, Herren HR and Gepts P. 2008. Long-distance pollen flow assessment through evaluation of pollinator foraging range suggests transgene escape distances. Proc. Natl. Acad. Sci., 105:13456-13461.
Peakall R and Smouse PE. 2006. GENALEX 6: genetic analysis in Excel. Population genetic software for teaching and research. Mol Ecol Notes 6:288-295.
Quin FM. 1997. Introduction. In „Advances in cowpea research„. Edited by Singh BB, Mohan RDR, Dashiell KE and Jackai LEN. IITA (Nigeria) - JIRCAS (Japan). 375.
Real LA. 1994. Ecological genetics. Princeton University Press, Princeton, New Jersey, USA.
Ritland K. 2002. Extensions of models for the estimation of mating systems using n independent loci. Heredity 88:221-228.
Second G and Trouslot P. 1980. Electrophorèse d'enzymes de riz (Oryza sp.). - ORSTOM, Paris.
Singh BB, Chambliss OL and Sharma B. 1997. Recent advance research in cowpea breeding. In „Advances in cowpea research‟. Edited by Singh BB, Mohan RDR, Dashiell KE and Jackai LEN. IITA (Nigeria) - JIRCAS (Japan). 375.
Slatkin M and Barton NH. 1989. A comparison of three indirect methods for estimating average levels of gene flow. Evolution 43:1349-1368.
Ueno S, Tomaru N, Yoshimaru H, Manabe T and Yamamoto S. 2002. Size-class differences in genetic structure and individual distribution of Camellia japonica L. in a Japanese old-growth evergreen forest. Heredity 89:120-126.
Vaillancourt RE, Weeden NF and Barnard J.1993. Isozyme diversity in the cowpea species complex. Crop Sci., 33:606-613.
Weir BS and Cockerham CC. 1984. Estimating Fstatistics for the analysis of population structure. Evolution 38:1358-1370.
Wendel JF and Weeden NF. 1989. Visualization and interpretation of plant isozymes. In „Isozymes in plant biology„. Edited by Soltis DE and Soltis PS. Chapman and Hall, London, UK. 5-45.
Workman PL and Niswander JD. 1970. Population studies on southern Indian tribes. II. Local genetic differentiation in the Papago. Am. J.Hum. Genet., 22:24-49.
Wright S. 1922. Coefficients of inbreeding and relationship. Am Nat 56: 330-338.
Wright S. 1951. The genetic structure of populations. Ann. Eugen. 15:313-354.
Wright S. 1965. The interpretation of population structure by F-statistics with special regard to systems of mating. Evolution 19:395-420.
Wright S. 1978. The evolution and genetics of population. Volume IV. Variability within and among natural populations. University of Chicago Press.
Yeh FC, Yang RC and Boyle T. 1999. POPGENE Release 1.31. Microsoft Windows-Based Freeware for Population Genetic Analysis. University of Alberta, Edmonton.
Young A, Boyle T and Brown T. 1996. The population genetic consequences of habitat fragmentation for plants. Trends Ecol Evol., 11:413-418.
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