Abstract
The Australian rodent, Uromys caudimaculatus, consists of two chromosome races, a) The Southern Race is characterized by the possession of two to twelve B-chromosomes. These vary considerably in size, morphology, and C- and G-banding characteristics, they behave as univalent at meiosis and are inherited in a random manner, b) The Northern Race lacks Bchromosomes, but possesses large blocks of distal C-positive heterochromatin on between 18 and 28 of the 46 chromosomes. The C-blocks may be entirely G-positive, entirely G-negative, or G-banded, suggesting heterogeneity within the C-blocks. There is extensive variation both between and within populations of the northern race in the number and size of the distal heterochromatic blocks. There is no apparent difference between the races in chiasma frequency. The northern race does have a much higher proportion of interstitial versus distal chiasmata, although it is probable that this is merely a reflection of lack of crossing over in the heterochromatic blocks rather than an actual shift of chiasma localisation within the euchromatin. Despite the extensive differences between the races in the amount and organization of constitutive heterochromatin, hybrids show no abnormalities at meiosis and they are fully fertile.
Similar content being viewed by others
References
Arnason, U., Pudom, I.F., Jones, K.W.: Conservation and chromosomal localization of DNA satellites in Balenopterid whales. Chromosoma (Berl.) 66, 141–159 (1978)
Arrighi, F.E., Hsu, T.C.: Localization of heterochromatin in human chromosomes. Cytogenetics 10, 81–86 (1971)
Baverstock, P.R., Watts, C.H.S., Hogarth, J.T.: Heterochromatin variation in the Australian rodent Uromys caudimaculatus. Chromosoma (Berl.) 397–403 (1976)
Baverstock, P.R., Watts, C.H.S., Hogarth, J.T.: Polymorphism of the X-chromosome, Y-chromosome and autosomes in the Australian hopping mice, Notomys alexis, N. cervinus and N. fuscus (Rodentia, Muridae). Chromosoma (Berl.) 61, 243–256 (1977)
Dev, V.G., Miller, D.A., Tantravahi, R., Schreok, R.R., Roderick, T.H., Erlanger, B.F., Miller, D.J.: Chromosome markers in Mus musculus. Differences in C-banding between the subspecies Mus musculus musculus and Mus musculus molossinus. Chromosoma (Berl.) 53, 335–344 (1975)
Ford, C.E., Evans, E.P.: Meiotic preparations from mammalian testes. In: Comparative mammalian cytogenetics (K. Benirschke, ed.) Berlin, Heidelberg, New York: Springer 1969
Fry, K., Salser, W.: Nucleotide sequences of HS-α satellite DNA from the kangaroo rat Dipodomys ordii and characterisation of similar sequences in other rodents. Cell 12, 1069–1084 (1977)
Hayata, I.: Chromosomal polymorphism caused by supernumerary chromosomes in the field mouse, Apodemus giliacus. Chromosoma (Berl.) 42, 403–414 (1973)
John, B., King, M.: Hetrochromatin variation in Cryptobothrus chrysophorus, III. Synthetic hybrids. Chromosoma (Berl.) 78, 165–186 (1980)
John, B., Miklos, G.L.G.: Functional aspects of satellite DNA and heterochromatin. Int. Rev. Cytol. 58, 1–114 (1979)
King, M.: C-banding studies on Australian Hylid frogs: secondary constriction structure and the concept of euchromatin transformation. Chromosoma (Berl.), 80, 191–217 (1980)
Ma, N.S.F., Jones, T.C.: Added heterochromatin segments in chromosomes of squirrel monkey (Saimiri sciureus). Folia primatol. 24, 282–292 (1975)
Mandahl, N.: Variation in C-stained chromosome regions in European hedgehogs (Insectivora, Mammalia). Hereditas (Lund) 89, 107–128 (1978)
Mascarello, J.T., Hsu, T.C.: Chromosome evolution in woodrats, genus Neotoma (Rodentia, Cricetidae). Evolution (Lawrence, Kans.) 30, 152–169 (1976)
Mascarello, J.T., Mazrimas, J.A.: Chromosomes of antelope squirrels (genus Ammospermophilus): A systematic banding analysis of four species with unusual constitutive heterochromatin. Chromosoma (Berl.) 64, 207–217 (1977)
Miklos, G.L.G., John, B.: Heterochromatin and satellite DNA in man: properties and prospects. Amer. J. Hum. Genet., 31, 264–280 (1979)
Miklos, G.L.G., Nankivell, R.N.: Telomeric satellite DNA functions in regulating recombination. Chromosoma (Berl.) 56, 143–167 (1976)
Müntzing, A.: Accessory chromosomes. In: Annual Rev. Genet. Vol. 8 (H.L. Roman, A. Campbell, and L.M. Sandier, eds.), p. 243–266. Palo Alto California: Annual Reviews Inc. 1974
Pathak, S., Hsu, T.C., Arrighi, F.E.: Chromosomes of Peromyscus (Rodentia, Cricetidae) IV. The role of heterochromatin in karyotypic evolution. Cytogenet. Cell Genet. 12, 315–326 (1973a)
Pathak, S., Hsu, T.C., Shirley, L.: Chromosome homology in the climbing rats, genus Tylomys (Rodentia: Cricetidae). Chromosoma (Berl.) 42, 215–228 (1973b)
Patton, J.L.: B-chromosome systems in the pocket mouse, Perognathus baileyi: Meiosis and C-band studies. Chromosoma (Berl.) 60, 1–14 (1977)
Seabright, M.: The use of proteolytic enzymes for the mapping of structural rearrangements in the chromosomes of man. Chromosoma (Berl.) 36, 204–210 (1972)
Sharma, T., Garg, G.S.: Constitutive heterochromatin and karyotype variation in the Indian pygmy mouse, Mus dunni. Genet. Res., (Camb.) 25, 189–191 (1975)
Yosida, T.H., Sagai, T.: Variation of C-bands in the chromosomes of several subspecies of Rattus rattus. Chromosoma (Berl.) 50, 283–300 (1975)
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Baverstock, P.R., Gelder, M. & Jahnke, A. Cytogenetic studies of the Australian rodent, Uromys caudimaculatus, a species showing extensive heterochromatin variation. Chromosoma 84, 517–533 (1982). https://doi.org/10.1007/BF00292853
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00292853