KARYOTYPE ANALYSIS OF THE COMMON MOLE RAT (TACHYORYCTES SPLENDENS) FROM DIFFERENT LOCALITIES IN ETHIOPIA

  • Ziyin Mihretie
  • Kifle Dagne
Keywords: Chromosome, Ethiopia, Karyotype, Tachyoryctes splendens.

Abstract

In the present study, karyotypes of the east African mole rat,Tachyoryctes splendens, specimens from nine localities in Ethiopia namely;
Bure, Chiro, Debre Sina, Entoto, Haramaya, Masha, Mugo, Sebeta and Ziway, were analyzed using conventional chromosome preparation method
from the bone marrow cells. 2n=48 chromosomes were counted for all the specimens of all the nine localities. The chromosomes fall into metacentric,
submetacentric, subtelocentric and telocentric classes, with the latter being the most frequent type. In all the cases, the X chromosome was the largest in the complement and it was metacentric, except for Entoto and Sebeta specimens, in which case it was submetacentric. The Y chromosome was smaller than the X chromosome and it was also metacentric in all the karyotypes except in Debre Sina where it was submetacentric. In all the
karyotypes, small autosomal metacentric chromosomes were present, but their number varied as three, four and five pairs in different karyotypes. Clear submetacentric autosomal chromosomes were observed in the karyotypes of Masha and Mugo specimens only. Autosomal fundamental number ranged from 52 to 66. Generally, karyotypic similarity corresponded with population geographic proximity. In total, six different karyotypic forms were recognized which can be grouped as Masha-Mugo, Bure, Debre Sina, Entoto-Sebeta, Ziway, and Haramaya-Chiro karyotypes. The presence of different numbers of metacentric autosomal chromosomes observed in different karyotypes, unaccompanied by a change in diploid chromosome number, could probably be due to pericentric inversions rather than due to Robertsonian translocations.

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References

Allen, E.M. (1939). A checklist of African mammals. Bull. Mus. Comp. Zool. Hav. 83:1-763.
Anderson, S. and Jones, K. (1967). Recent Mammals of the World. The Ronald Press,New York.
Aniskin, V.M., Lavrenchenko, L.A., Varshaviskii, A.A. and Milishnikov, A.N. (1997). Karyotypes and chromosomal differentiation of two Tachyoryctes species (Rodentia, Tachyoryctinae) from Ethiopia. Russ. J. Genet. 33(9):1266-1272.
Arnason, U. (1972). The role of chromosomal rearrangement in mammalian species with special reference to Cetacea and Pinnipedia. Hereditas 70:113-118.
Baker, R. J. (1970). The role of karyotypes in phylogenetic studies of bats. In: About Bats,pp. 303-312 (Slaughter, B.H. and Walton, D. W., eds.). Southern Methodist Univ.Press, Dallas.
Baskevich, M.I., Orlov, V.N., Afework Bekele and Asefa Mebrate (1993). Notes on the karyotype of Tachyoryctes splendens (Ruppell 1836) (Rodentia: Rhizomyidae) from Ethiopia. Trop. Zool. 6:81-88.
Bush, G.L., Case, S.M., Wilson, A.C. and Patton, J.L. (1977). Rapid speciation and chromosomal evolution in mammals. Proc. Natl. Acad. Sci. USA 74(9):3942-3946.
Corbet, G.B. and Hill, J.E. (1991). A World List of Mammal Species. 3rd ed. Oxford University Press, London.
Ellerman, J.R. (1941). The Families and Genera of Living Rodents with a List of Named Forms (1758-1936), Vol. 2. British Museum (N. H.), London.
Fredga, K. (1977). Chromosomal changes in vertebrate evolution. Proc. R. Soc. Lond. B.199:377-397.
Garber, E.D. (1979). Cytogenetics: An Introduction. Tata McGraw-Hill Publishing Company, Ltd., New Delhi.
Gibson, L.J. (1984). Chromosomal changes in mammalian speciation: A literature review.Origins 11 (2):67-89.
Honacki, J.H., Kinman, K.E. and Koeppl, J.W. (1982). Mammal Species of the World.Allen Press, Lawrence.
Jarvis, J.U.M and Sale, J.B. (1971). Burrowing and burrow patterns of east African mole rats, Tachyoryctes, Heliophobius and Heterocephalus. J. Zool. London 163:451-479.
Lavrenchenko, L.A., Milishnikov, A.N., Aniskin, V.M., Varshavskii, A.A. and Woldegabriel Gebrekidan (1997). The genetic diversity of small mammals of the Bale Mountains, Ethiopia. SINET: Ethiop. J. Sci. 20(2):213-233.
Levan, A., Fredga, K. and Sanderberg, A.A. (1964). Nomenclature for centromeric position on chromosomes. Hereditas 52:201-220.
Nevo, E. (1979). Adaptive convergence and divergence of subterranean mammals. Annu. Rev. Ecol. Syst. 10:269-308.
Nevo, E., Filippucci, M.G., Redi, C.A. and Beiles, A. (1994). Chromosomal speciation and adaptive radiation of mole rats in Asia Minor correlated with increased ecological stress. Proc. Natl. Acad. Sci. USA 91:8160-8164.
Nowak, R.M. (1991). Walker's Mammals of the World, Vol. II. 5th ed. The John Hopkins University Press, Baltimore & London.
Robbins, L.W. and Baker, R.J. (1978). Karyotypic data for African mammals, with a description of an in vivo bone marrow technique. Bull. Carnegie Mus. Nat. Hist.6:188-193.
Searle, J.B., Hubner, R., Wallace, B.M.N. and Garagna, S. (1990). Robertsonian variation in wild mice and shrews. Chrom. Today 10:253-263.
Sewnet Mengistu and Afework Bekele (2003). Geographic variations in the Ethiopian common mole rat (Tachyoryctes splendens) based on morphometry. Ethiop. J. Biol. Sci. 2(1):73-89.
Sokolov, V.E. (1977). Mammal Systematics: Order Logomorpha, Rodentia. High School, Moscow.
Toloza, A.C., Scaglia, O. and Massarini, A.I. (2004). Cytogenetic analysis of Ctenomys opimus (Rodentia, Octodontidae) from Argentina. J. Neotrop. Mamm. 11(1):115-118.
Wahrman, J., Goitein, R. and Nevo, E. (1969). Mole rat Spalax: Evolution significance of chromosome variation. Science 164:82-84.
White, M.J.D. (1975). Chromosomal re-patterning: Regularities and restrictions. Genetics Suppl.79:63-72.
Yalden, D.W., Largen, M.J. and Kock, D. (1976). Catalogue of the mammals of Ethiopia 2. Insectivora and Rodentia. Mon. Zool. It. (NS), Suppl. 8:1-118.
Published
2012-09-15