Summary
Nuclear DNA contents were estimated by microdensitometry in five species ofAkodon rodents:Adodon molinae, A. dolores, A. mollis, A. azarae, Bolomys obscurus) and in three chromosomal varieties ofA. molinae (2n=42; 2n=43, 2n=22). The data obtained showed that the species with the highest DNA content wasB. obscurus, followed in order of decreasing genome size byA. molinae, A. mollis, A. dolores andA. azarae. InA. molinae the forms with 2n=42 chromosomes had the lowest and the forms with 2n=44 the highest amount of DNA, while the forms with 2n=43 had intermediate DNA contents. The variation in DNA amount detected inA. molinae was interpreted as a phenomenon of amplification occurring in the chromosomal areas involved in the chromosomal rearrangement giving rise to the polymorphism exhibited by this species. The DNA contents of shared chromosomes (chromosomes with similar size, morphology and G banding pattern, which are found in two or more phylogenetically related species), were compared and correlated with values of total nuclear DNA. The information obtained indicates that: (a) shared chromosomes have variable amounts of DNA: (b) in a given species there is a correlation between the amount of nuclear and chromosomal DNA in most shared chromosomes (and perhaps in most of the chromosmal complement), e.g., the higher the amount of nuclear DNA, the higher the content of DNA in shared chromosomes; (c) some chromosomes may undergo processes of amplification or deletion restricted to certain regions and usually related with mechanisms of chromosomal rearrangements. The data obtained seem to indicate that the genome size of a species depends on the interaction of two independent mechanisms: (1) a general process of DNA variation which acts coincidentally in the same direction (gain or loss) in the whole chromosome complement without disturbing the mechanism of chromosome condensation producing G bands and (2) restricted processes of DNA variations (amplifications or deletions) which act on single chromosomes and which are in most cases related with chromosmal rearrangements.
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References
Altman PL, Katz DD (1976) Cell Biology I. Fed Am Soc Exp Biol, p 367
Bachman K (1972) Genome size in mammals. Chromosoma 37:85–93
Bedi KS, Goldstein DJ (1976) Apparent anomalies in nuclear Feulgen DNA content. Role of systematic microdensitometric errors. J Cell Biol 71:68–88
Bernocchi G, De Stefano GF, Porcelli F, Redi CA, Manfredi-Romanini MG (1976) Feulgen reaction hydrolysis kinetics in interphase and metaphase. Nucleus 19:141–149
Baimai V (1977) Chromosomal polymorphisms of constitutive heterochromatin and inversions in Drosophila. Genetics 85:85–93
Bianchi NO, Bianchi MS (1969) Origin of the pattern and chronology of chromosome replication in vertebrates. Genet Suppl 61:275–287
Bianchi NO, Contreras J (1967) The chromosomes of the field mouseAkodon azarae (Rodentia Cricetidae) with special reference to sex chromosome anomalies. Cytogenetics 6:306–313
Bianchi NO, Merani MS (1980) Chromosome 1 polymorphism and viability inAkodon (Rodentia Cricetidae), In: Reig OA (ed) Ecology and Genetics of Animal Speciation, Universidad Simón Bolivar, Caracas, Venezucla, p 211
Bianchi NO, Merani MS, Lizarralde M (1979) Cytogenetics of the South American Akodont rodents (Cricetidae). VI. Polymorphism inAkodon dolores (Thomas). Genética 50:99–104
Bianchi NO, Merani MS, Lizarralde M, Oliveira D (1979) Cytogenetics of the South American Akodont rodents (Cricetidae). V. Segregation of chromosome No1 polymorphism inAkodon molinae. Experientia 35:1438–1439
Bianchi NO, Reig O, Merani MS (1982) Cytogenetics of the South American Akodont rodents (Cricetidae). XI. Measurements of karyological distances at the generic and suprageneric levels (in preparation)
Bianchi NO, Reig OA, Molina OJ, Dulout FN (1971) Cytogenetics of the South American Akodont rodents (Cricetidae). I. A progress report of Argentinian and Venezuelan forms. Evolution 21:724–736
Bianchi NO, Vidal-Rioja L, Bianchi MS (1973) Constitutive heterochromatin, G bands and Robertsonian rearrangements in the chromosomes ofAkodon molinae (Rodentia cricetidae). Can J Genet Cytol 15:855–861
Bianchi NO, Vidal-Rioja L, Bianchi MS (1976) Cytogenetics of the South AmericanAkodont rodents (Cricetidae). II. Interspecific homology of G banding patterns. Cytologia 41:139–144
Capanna E, Manfredi-Romanini MG (1971) Nuclear DNA content and morphology of the karyotype in certain paleoartic michroptera. Caryologia 23:79–82
Catalá A, Vidal-Rioja L, Bianchi NO (1981) Liver chromatin fractions inMus andAkodon. The concept of constitutive heterochromatin. Mol Cel Biochem 36:135–141
Courot M, Hochereau de Reviers MTM, Ortavant R (1970) Spermatogenesis. In: Jonson AD, Gomes WR, VanDemark NL (eds) The Testis. Academic Press, New York, pp 339–432
Garagna S, Formenti D (1981) DNA content variability in several species of Australian and South American marsupials. Boll Zool 48
Geldhill BL, Campbell GL (1973) Microfluorometric comparison of chromatin during cytodifferentiation. In: Fluorescence Techniques in Cell Biology. Springer-Verlag, Berlin Heidelberg New York, pp 151–162
Hinegardner R (1980) Evolución del tamaño del genoma. In: Ayala FJ (ed) Evolución molecular, Omega SA, Barcelona, España p 165
Itikawa O, Ogura Y (1954) The Feulgen reaction after hydrolysis at room temperature. Stain Technol 29:13–15
Keyl HG (1961) Chromosomenevolution bei Chironomus. I. Strukturabwandlungen an Speicheldrüsen-Chromosomen. Chromosoma 12:26–47
Lobato L, Cantos C, Araujo B, Bianchi NO, Merani MS (1982) Cytogenetics of the South American Akodont rodents (Cricetidac). X.Akodon mollis: a species with XY females and B chromosomes. Genética 57(3):199–205
Manfredi-Romanini MG, Fraschini A, Formenti D, Pellicciari C, Redi CA (1981) Analysis of some cytophotochemical parameters for a definition of the chromatin status. Acta Histochemica Suppl XXIV:18–198
Manfredi-Romanini G (1973) The DNA nuclear content and the evolution of vertebrates. In: Chiarelli AB, Capanna E (eds) Cytotaxonomy and vertebrate evolution. Academic Press, London New York, p 39
Manfredi-Romanini MG, Capanna E (1971) Contenuto in DNA nei nuclei postcinetici in due popolazioni cromosomicamente differenti diRattus rattus (L) Rend Qcc Naz Lincei (Classe Scienze) Ser VIII 51:105–109
Mirsky AE, Ris H (1951) The desoxiribonucleic acid content of animal cells and its evolutionary significance. J Gen Physiol 34:451–462
Olert J, Schmid M (1978) Comparative analysis of karyotypes in European shrew species. I. The sibling speciesSorex araneus andS. gemellus: Q bands, G bands and position of NORs. Cytogenet Cell Genet 20:308–322
Pellicciari C, Formenti D, Redi CA, Manfredi-Romanini MG (1982) DNA content variability in Primates. J Hum Evol 11:131–141
Reig OA (1980) A new fossil genus of South American cricetid rodents allied to Wiedomys with an assesment of the Sigmodontinae. J Zool London 192:259–281
Reig OA (1981) Teorla del Origen y Desarrollo de la Fauna de Mamiferos de América del Sur, Monogr. Naturac Mus. Municipal de Ciencias Naturales: Lorenzo Scaglia, Mar del Plata, Argentina, pp 1–162
Smith GP (1976) Evolution of repeated DNA sequences by unequal crossover. Science 191:528–535
Stock AD (1975) Chromosome banding pattern homology and its phylogenic implications in the bat generaCarollia andChoeroniscus. Cytogenet Cell Genet 14:34–41
Stock AD (1976) Chromosome banding pattern relationships in hares, rabbits and pikas (orderLagomorpha). A philetic interpretation. Cytogenet Cell Genet 17:78–83
Stock AD, Hsu TC (1973) Evolutionary conservatism in the arrangement of genetic material. A comparative analysis of chromosome banding between the Rhesus macaque (2n=42, 84 arms) and the African green monkey (2n=60, 120 arms). Chromosoma 43:211–224
Stock AD, Mengden GA (1975) Chromosome banding patterns between birds, turtles, snakes and amphibians. Chromosoma 50:69–77
Vidal-Rioja L, Bianchi NO, Catalá A (1982) DNA ofAkodon (Rodentia Cricetidae). II. Molecular hybridization of repetitive DNA sequences. J Genet Cytol (in press).
Vidal-Rioja L, Semorile L, Bianchi NO (1979) DNA ofAkodon (Rodentia Cricetidae). I. Biophysical characterization. Biochem Genet 17:297–303
White MJD (1977) Animal Cytology and Evolution, Cambridge Univ. Press, London, New York Melborne 3rd ed
Wurster-Hill DH, Gray CW (1973) Giemsa banding patterns in the chromosomes of twelve species of cats (Felidae). Cytogenet Cell Genet 12:377–397
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This work was supported by grants from Conicet and CIC
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Bianchi, N.O., Redi, C., Garagna, C. et al. Evolution of the genome size inAkodon (Rodentia, Cricetidae). J Mol Evol 19, 362–370 (1983). https://doi.org/10.1007/BF02101640
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DOI: https://doi.org/10.1007/BF02101640