Chromosoma

, Volume 72, Issue 2, pp 225–240

Autosomal synaptonemal complexes and sex chromosomes without axes in Triatoma infestans (Reduviidae; Hemiptera)

  • Alberto J. Solari
Article

Abstract

Meiotic and somatic cells at interphase in Triatoma infestans are characterized by the formation of a large chromocenter, which was assumed to contain the whole of the three large pairs of autosomes and the sex chromosomes. Observations with C-banding techniques show that the chromocenter is formed only by the terminal and subterminal heterochromatic blocks of the three large pairs of autosomes and the sex chromosomes. During pachytene the two largest autosomal pairs loop on themselves and their condensed ends form the chromocenter, together with the single heterochromatic end of the third autosomal pair. The X and Y chromosomes seem to associate with these condensed ends by their affinity for C-heterochromatin. During a very short pachytene stage, bivalents and synaptonemal complexes (SCs) are observed. Pachytene is followed by a very long diffuse stage, during which SCs are disassembled, multiple complexes aggregate on the inner face of the chromocenter and finally all complexes disappear and a dense material is extruded to the cytoplasm through the annuli. The 3-dimensional reconstruction of early pachytene chromocenters show 3 SCs entering and tunnelling the chromocenter, while during mid-pachytene 4 SCs enter this mass and a 5th SC is in a separate small mass. The looping of a whole SC which has both ends in the chromocenter was shown by the reconstructions. These data are interpreted as the progressive looping of the two largest bivalents during pachytene, forming finally the association of 5 bivalent ends corresponding to the 5 C-banding blocks of the large autosomal pairs. No single axis or SC that could be ascribed to the sex chromosomes was found. This agrees with the pachytene microspreads, which show only 10 SCs corresponding to the autosomal bivalents. The X and Y chromosomes are enclosed in the chromocenter, as shown by the unravelling chromocenters at diplotene-diakinesis. Thus the sex chromosomes do not form axial condensations, and this fact may be related to the ability of the X and Y chromosomes to divide equationally at metaphase I. SCs

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Barth, R.: Estudos anatomicos e histologicos sobre a subfamilia triatominae (Heteroptera, Reduviidae). V. Anatomia do testiculo e espermio-citogenese do Triatoma infestans. Mem. Inst. Oswald Cruz 54, 135–229 (1956)Google Scholar
  2. Carpenter, A.T.C.: Electron microscopy of meiosis in Drosophila melanogaster females: II: The recombination nodule — a recombination-associated structure at pachytene? Proc. Nat. Acad. Sci. (Wash.) 72, 3186–3189 (1975)Google Scholar
  3. Counce, S.J., Meyer, G.F.: Differentiation of the synaptonemal complex and the kinetochore in Locusta spermatocytes studied by whole mount electron microscopy. Chromosoma (Berl.) 44, 231–253 (1973)Google Scholar
  4. Craig-Cameron, T.A., Southern, D.I., Pell, P.E.: Chiasmata and the synaptonemal complex in male meiosis of Glossina. Cytobios 8, 199–207 (1973)Google Scholar
  5. Drets, M.E., Stoll, M.: C-banding and non-homologous associations in Gryllus agentinus. Chromosoma (Berl.) 48, 367–390 (1974)Google Scholar
  6. Fletcher, H.L.: Localised chiasmata due to partial pairing: a 3-D reconstruction of SC's in male Stethophyma grossum. Chromosoma (Berl.) 65, 247–270 (1978)Google Scholar
  7. Gillies, C.B.: Reconstruction of the Neurospora crassa pachytene karyotype from serial sections of synaptonemal complexes. Chromosoma (Berl.) 35, 119–130 (1972)Google Scholar
  8. Gillies, C.B.: Synaptonemal complex and chromosome structure. Ann. Rev. Genet. 9, 91–109 (1975)Google Scholar
  9. Hughes-Schrader, S., Schrader, F.: The kinetochore of the Hemiptera. Chromosoma (Berl.) 12, 327–350 (1961)Google Scholar
  10. John, B., Lewis, K.R.: The meiotic system. Protoplasmatologia VI/F1. Wien, New York: Springer 1965Google Scholar
  11. Luykx, P.: The organization of meiotic chromosomes. In: The cell nucleus, V. II (H. Busch, ed.). New York: Academic Press 1974Google Scholar
  12. Maudlin, I.: Giemsa banding of metaphase chromosomes in triatomine bugs. Nature (Lond.) 252, 392–393 (1974)Google Scholar
  13. Meyer, G.F.: The fine structure of spermatocyte nuclei of Drosophila melanogaster. Europ. Reg. Conf. Electron Microsc., Delft, 2, 951–954 (1960)Google Scholar
  14. Moses, M.J.: Synaptinemal complex. Ann. Rev. Genet. 2, 363–412 (1968)Google Scholar
  15. Moses, M.J.: Synaptonemal complex karyotyping in spermatocytes of the Chinese hamster (Cricetulus griseus). I. Morphology of the autosomal complement in spread preparations. Chromosoma (Berl.) 60, 99–125 (1977)Google Scholar
  16. Nicklas, B.R.: Recurrent pole to pole movements of the sex chromosome during prometaphase I in Melanoplus differentialis spermatocytes. Chromosoma (Berl.) 12, 97–115 (1961)Google Scholar
  17. Rasmussen, S.W.: Ultrastructural studies of meiosis in males of the c(3)G17 mutant of Drosophila melanogaster Meigen. C.R. Trav. Lab. Carlsberg 40, 163–173 (1975)Google Scholar
  18. Ruthmann, A., Dahlberg, R.: Pairing and segregation of the sex chromosomes in X1-X2-males of Dysdercus intermedius with a note on the kinetic organization of heteropteran chromosomes. Chromosoma (Berl.) 54, 89–97 (1976)Google Scholar
  19. Schreiber, G., Pellegrino, J.: Eteropicnosi di autosomi come possibile meccanismo di speciazione (Ricerche citologiche su alcumi Emitteri neotropici). Sci. genet. 3, 215–226 (1950)Google Scholar
  20. Smith, P.A., King, R.C.: Genetic control of synaptinemal complexes in Drosophila melanogaster. Genetics 60, 335–351 (1968)Google Scholar
  21. Solari, A.J.: The spatial relationship of the X and Y chromosomes during meiotic prophase in mouse spermatocytes. Chromosoma (Berl.) 29, 217–236 (1970)Google Scholar
  22. Solari, A.J.: The behavior of the XY pair in mammals. Int. Rev. Cytol. 38, 273–317 (1974a)Google Scholar
  23. Solari, A.J.: The relationship between chromosomes and axes in the chiasmatic XY pair of the armenian hamster (Cricetulus migratorius). Chromosoma (Berl.) 48, 89–106 (1974b)Google Scholar
  24. Solari, A.J., Ashley, T.: Ultrastructure and behavior of the achiasmatic, telosynaptic XY pair of the sand rat (Psammomys obesus). Chromosoma (Berl.) 62, 319–336 (1977)Google Scholar
  25. Solari, A.J., Bianchi, N.: The synaptic behavior of the X and Y chromosomes in the marsupial Monodelphis dimidiata. Chromosoma (Berl.) 52, 11–25 (1975)Google Scholar
  26. Solari, A.J., Counce, S.J.: Synaptonemal complex karyotyping in Melanoplus differentialis. J. Cell Sci. 26, 229–250 (1977)Google Scholar
  27. Southern, D.I., Craig-Cameron, T.A., Pell, P.E.: The meiotic sequence in Glossina morsitans morsitans. Trans. R. Soc. Trop. Med. Hyg. 66, 145–149 (1972)Google Scholar
  28. Sumner, A.T.: A simple technique for demonstrating centromeric heterochromatin. Exp. Cell Res. 75, 304–306 (1972)Google Scholar
  29. Ueshima, N.: Cytotaxonomy of the Triatominae (Reduviidae: Hemiptera). Chromosoma (Berl.) 18, 97–122 (1966)Google Scholar
  30. Westergaard, M., Wettstein, D. von: The synaptinemal complex. Ann. Rev. Genet. 6, 71–110 (1972)Google Scholar
  31. Yunis, J., Yasmineh, W.G.: Heterochromatin, satellite DNA and cell function. Science 174, 1200–1209 (1971)Google Scholar

Copyright information

© Springer-Verlag 1979

Authors and Affiliations

  • Alberto J. Solari
    • 1
  1. 1.Facultad de MedicinaCentro de Investigacions en ReproduccionBuenos AiresArgentina

Personalised recommendations