Biochemical genetic markers to identify two morphologically similar South African Mastomys species (Rodentia: Muridae)
Introduction
The Mastomys species complex of mice is widely distributed in South Africa, especially the so-called Multimammate mice, Mastomys coucha and M. natalensis. The limits of their distribution are only provisional at this stage (Skinner, 1990), but it is known that they are sympatric in some areas, and allopatric in others. Mastomys coucha acts as a reservoir for the Rickettsian Yersinia pestis, the organism causing Plague (Dippenaar et al., 1993).
At present, three diagnostic forms of plague are known: bubonic, primary pneumonic and primary Septicaemic. Bubonic plague, which is the most common type in epidemics, is fatal in about 25–50% of untreated cases. Pneumonic plague, a highly contagious (airborne) form, and Septicaemic plague, a generalised blood infection, are rarer forms, and usually fatal (Roberts et al., 1996). Apart from Bubonic plague, this species complex is also a reservoir for the Banzi and Witwatersrand viruses (Dippenaar et al., 1993) as well as a recently emerged disease in forested West Africa. Lassa fever is an infection caused by an arenavirus, and has a high mortality rate, even in patients with hospital care (15–20% fatal). Mastomys natalensis, being a documented carrier of Lassa Fever also carries a Lassa-like virus called Mopeia. Its effect on man is yet to be established or researched (Murray et al., 1995).
Morphologically, both species are almost identical in all visible characteristics, and were originally regarded as one (De Graaf, 1981) M. natalensis. However, Gordon (1984) has shown that, at the very least, both species are distinguishable by ethological and micro-morphological characteristics, by their chromosome number, and characteristic haemoglobin variations. More recently, Dippenaar et al. (1993) used multivariate analysis of cranial characteristics to distinguish between the two species. However, 50% of the specimens collected at a sympatric locality were identified differently according to the latter method.
In the present study, we examined new material of two allopatric populations of M. coucha and M. natalensis aimed at identifying species characteristic genetic markers. Allozyme and haemoglobin variations were analysed comparatively.
Section snippets
Materials and methods
Tissue extracts of 24 individuals of M. coucha caught at Montgomery Park, Johannesburg (26°09’22’’S, 27°58’58’’E) and 20 individuals of M. natalensis caught at La Lucia ridge in Durban North (29°44’44’’S, 31°03’09’’E), were analysed electrophoretically using standard horizontal starch gels and homogeneous polyacrylamide gels (Fig. 1). The localities were also studied to determine if there was a relationship between habitat types and the distribution of these two species (Fig. 2). Specimens that
Ecology and distribution
It was not previously possible to accurately describe the geographic distribution and habitat requirements of either species, as a result of the extreme morphological similarity of M. natalensis and M. coucha, and the fact that the genetic composition of only a relatively small number of individuals has been studied. It does however seem likely that differences in the habitat requirements of the two species do exist. Fig. 2 shows the localities of the M. coucha and M. natalensis populations
Acknowledgments
We thank Sasol far funding this project.
References (24)
- et al.
Electrotransfer of proteins following polyacrylamide gel electrophoresis — nitrocellulose versus nylon membranes
J. Immunol. Methods
(1988) - et al.
A Comparative Summary of Genetic Distances in the VertebratesPatterns and Correlations
Evol. Biol.
(1982) Population and Evolutionary Genetics
(1982)The Rodents of Southern Africa
(1981)- et al.
Diagnostic morphometrics of two medically important southern African rodents, Mastomys natalensis and M. coucha (Rodentia: Muridae)
South African J. Sci.
(1993) - Falk, T.M., Abban, E.K., Oberst, S., Villwock, W., Pullin, R.S.V., Renwrantz, L., 1996. A biochemical laboratory manual...
- et al.
Heterogeneity and subunit composition of the haemoglobins of 5 tilapiine species (Teleostei, Cichlidae) of the genera Oreochromis and Sarotherodon
J. Comparative Physiol. B
(1998) - Ferreira, J.T., Grant, W.S., Avtalion, R.R., 1984. Workshop on Fish Genetics. CSIR Special Publications, Pretoria, p....
- Gordon, D.H., 1984. Evolutionary genetics of the praomys (Mastomys) natalensis species complex (Rodentia: Muridae)....
- et al.
Handbook of Enzyme Electrophoresis in Human Genetics
(1976)
Estimation of average heterozygosity and genetic distance from a small number of individuals
Genetics
Lactate dehydrogenase isozyme patterns of fish
J. Expl. Zool.
Cited by (21)
Chapter 7 - Biology and Diseases of Other Rodents
2015, Laboratory Animal Medicine: Third EditionDaily rhythms of body temperature and heat production of sibling mastomys species from different ecosystems - The response to photoperiod manipulations
2008, Comparative Biochemistry and Physiology - A Molecular and Integrative PhysiologyLack of between- and within-species isoenzyme variability in Aquila eagles (Aves: Accipitriformes)
2007, Biochemical Systematics and EcologyCitation Excerpt :Improving the methods of separation of isoenzymes could be of some help, because different electrophoresis buffer systems can reveal hidden variability. The genetic distances (in allozyme studies they have been measured mainly as Nei's and/or Rogers' distances) between avian taxa and populations are usually smaller than those among other vertebrates (e.g. mammals; Gutiérrez et al., 1983; Valvo et al., 1997; Smit et al., 2001; but see Schreiber et al., 2001; van Wyk et al., 2001), and the genetic variability in raptors is often lower than other avian taxa. This holds true for both between-(Schreiber and Weitzel, 1995; van Wyk et al., 2001) or within-species variation (e.g. Negro and Hiraldo, 1994; Schreiber et al., 2001).
Palaeoenvironments and palaeodiets of mid-Pliocene micromammals from Makapansgat Limeworks, South Africa: A stable isotope and dental microwear approach
2006, Palaeogeography, Palaeoclimatology, PalaeoecologyMolecular identification of four cryptic species of Mastomys (Rodentia, Murinae)
2005, Biochemical Systematics and EcologyCitation Excerpt :data). In South Africa, haemoglobin patterns seemed to distinguish sympatric populations of M. coucha and M. natalensis (Green et al., 1980); recently, Smit et al. (2001) found three additional loci with diagnostic alleles between these two species. Karyology and electrophoresis show important limitations, as they require fresh or frozen material and cannot be applied to ethanol-fixed or museum samples.
Renal physiology of two southern African Mastomys species (Rodentia: Muridae): A salt-loading experiment to assess concentrating ability
2004, Comparative Biochemistry and Physiology - A Molecular and Integrative Physiology