Journal of Genetics

, 31:119 | Cite as

Meiosis inCrepis

II. Failure of pairing inCrepis capillaris (L.) wallr
  • M. Margaret Richardson


Part I.

1. Univalent formation in progeny from a diploid branch of a haploid individual ofCrepis capillaris belonging to theX strain is caused through failure of chiasma formation between homologous chromosomes which are shown to be regularly associated at pachytene.

2. A significant difference in the amount of univalent formation is found between two plants, and between two buds on the same plant.

3. Chiasma frequency is reduced in all three kinds of bivalents, and there is an almost direct relation between the amount of chiasma formation and the size of chromosomes. This is shown by the percentage of univalents and the mean number of chiasmata per bivalent.

4. Univalent homologous chromosomes frequently lie in juxtaposition at diakinesis. This is considered to be due to their previous association and coiling at pachytene and early diplotene.

Part II.

5. TheA bivalents in a single plant ofCrepis capillaris have a reduced frequency and an abnormal distribution of chiasmata. In bivalents with single interstitial chiasmata, 95 per cent. have the chiasma in a subterminal position at the end of the long arm. Univalents of these chromosomes are occasionally found, and unpaired threads are observed at pachytene. Chiasma formation and possibly pairing are therefore restricted in one region of the chromosome.


Homologous Chromosome Chiasma Frequency Chiasma Formation Spindle Attachment Restitution Nucleus 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


  1. Beadle, G. W. (1930). “Genetical and cytological studies of Mendelian asynapsis inZea mays.”Mem. Cornell agric. Exp. Sta. No. 129, 1–23.Google Scholar
  2. -- (1931). “A gene in maize for supernumerary cell divisions following meiosis.”Ibid. No. 135.Google Scholar
  3. —— (1932a). “A gene for sticky chromosomes inZea mays.”Z. indukt. Abstamm.-u. VerebLehre,63, 195–217.CrossRefGoogle Scholar
  4. —— (1932b). “Genes in maize for pollen sterility.”Genetics,17, 413–32.PubMedGoogle Scholar
  5. —— (1932c). “A gene inZea mays for failure of cytokinesis during meiosis.”Cytologia,3, 142–55.Google Scholar
  6. —— (1933). “Further studies of asynaptic maize.” Ibid.,4, 269–87.Google Scholar
  7. Blakeslee, A. F. (1928).Yearb. Carneg. Instn. 27, 42.Google Scholar
  8. Bridges, C. B. (1927). “The relation of the age of the female to crossing-over in the third chromosome ofDrosophila melanogaster.”J. gen. Physiol. 8, 689–700.CrossRefGoogle Scholar
  9. Darlington, C. D. (1932).Recent Advances in Cytology.Google Scholar
  10. Gowen, John Whittemore (1933). “Meiosis as a genetic character inDrosophila melanogaster.”J. exp. Zool. 65, 83–106.CrossRefGoogle Scholar
  11. Heilborn, Otto (1930). “Temperature und Chromosomenkonjugation.”Svensk bot. Tidskr. 24, 12–25.Google Scholar
  12. Hollingshead, Lillian (1930a). “Cytological investigations of hybrids and hybrid derivatives ofCrepis capillaris andCrepis tectorum.”Univ. Calif. Publ. agric. Sci. 6, 55–94.Google Scholar
  13. —— (1930b). “A cytological study of haploidCrepis capillaris plants.” Ibid.6, 107–34.Google Scholar
  14. —— (1930c). “A lethal factor inCrepis effective only in an interspecific hybrid.”Genetics,15, 114–40.PubMedGoogle Scholar
  15. —— (1932). “The occurrence of unpaired chromosomes in hybrids between varieties ofTriticum vulgare.”Cytologia,3, 119–41.Google Scholar
  16. Lesley, M. M. andFrost, H. B. (1927). “Mendelian inheritance of chromosome shape inMatthiola.”Genetics,12, 449–60.PubMedGoogle Scholar
  17. Moffett, A. A. (1932). “Chromosome studies inAnemone. I. A new type of chiasma behaviour.”Cytologia,4, 26–37.Google Scholar
  18. Philp, J. andHuskins, C. L. (1931). “The cytology ofMatthiola incana R.Br., especially in relation to the inheritance of double flowers.”J. Genet. 24, 359–404.CrossRefGoogle Scholar
  19. Plough, H. H. (1917). “The effect of temperature on crossing-over inDrosophila.”J. exp. Zool. 24, 147–209.CrossRefGoogle Scholar
  20. Richardson, M. Margaret (1935). “Meiosis inCrepis. I. Pachytene association and chiasma behaviour inCrepis capillaris (L.) Wallr. andC. tectorum L.”J. Genet. 31, 101–17.Google Scholar
  21. Sax, K. (1931). “Chromosome ring formation inRhoeo discolor.”Cytologia,3, 36–53.Google Scholar

Copyright information

© Indian Academy of Sciences 1935

Authors and Affiliations

  • M. Margaret Richardson
    • 1
  1. 1.Division of GeneticsUniversity of California, and John Innes Horticultural InstitutionMerton

Personalised recommendations