Access

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

If You Use a Screen Reader

This content is available through Read Online (Free) program, which relies on page scans. Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.

Mating Types in Paramecium Aurelia: Diverse Conditions for Mating in Different Stocks; Occurrence, Number and Interrelations of the Types

T. M. Sonneborn
Proceedings of the American Philosophical Society
Vol. 79, No. 3 (Sep. 30, 1938), pp. 411-434
Stable URL: http://www.jstor.org/stable/984858
Page Count: 24
  • Read Online (Free)
  • Subscribe ($19.50)
  • Cite this Item
Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Mating Types in Paramecium Aurelia: Diverse Conditions for Mating in Different Stocks; Occurrence, Number and Interrelations of the Types
Preview not available

Abstract

Mating types have been found in four species of Paramecium, in addition to the two previously reported: in P. trichium and P. calkinsi, by Sonneborn, and in P. multimicronucleatum and P. caudatum, by Gilman and by Giese and Arkoosh. Analysis of 26 stocks of P. aurelia, collected between North Carolina and Massachusetts and in California, shows that they are divisible into three groups, each of which consists of two mating types. Any member of one of the two types will conjugate with any member of the other, but not ordinarily with a member of its own type. The two types of group 1 are designated I and II; those of group 2 are types III and IV; those of group 3 are types V and VI. Group 1 includes 9 of the stocks; five of these (all from one source) consist exclusively of mating type I; each of the other four (from diverse sources) contains both types I and II. Group 2 includes 13 of the stocks (from diverse sources); 12 of them contain mating types III and IV, the other one has yielded type IV only. These two types give the characteristic clumping reaction and conjugate when mixed at night or early morning at temperatures not exceeding 25° C., best at 17° to 19° C. The percentage of conjugation obtained depends upon the temperature both before and during mixture of the types. Group 3 includes three of the stocks (from diverse sources); each of these contains mating types V and VI. These react and conjugate between 1 A. M. and 1 P. M. at temperatures not exceeding 27° C. Their diurnal periodicity in reactivity is a consequence of the alternation of light and darkness, visible light suppressing reactivity. Mating types appear to be of universal occurrence in P. aurelia; "non-conjugating" or rarely conjugating stocks seem not to exist. Some stocks appear, however, to consist exclusively of one type, and in order to get these to conjugate, they must be mixed with the appropriate type from another stock. A weak clumping reaction, never followed by conjugation, regularly occurs under favorable conditions in mixtures of types II and V. Hence, types I and V are similar in that both react with type II, and types II and VI are similar in that both react with type V. This suggests that these two pairs of types, and possibly all three pairs, may have originated as modifications of a single original pair of types.

Page Thumbnails

  • Thumbnail: Page 
411
    411
  • Thumbnail: Page 
412
    412
  • Thumbnail: Page 
413
    413
  • Thumbnail: Page 
414
    414
  • Thumbnail: Page 
415
    415
  • Thumbnail: Page 
416
    416
  • Thumbnail: Page 
417
    417
  • Thumbnail: Page 
418
    418
  • Thumbnail: Page 
419
    419
  • Thumbnail: Page 
420
    420
  • Thumbnail: Page 
421
    421
  • Thumbnail: Page 
422
    422
  • Thumbnail: Page 
423
    423
  • Thumbnail: Page 
424
    424
  • Thumbnail: Page 
425
    425
  • Thumbnail: Page 
426
    426
  • Thumbnail: Page 
427
    427
  • Thumbnail: Page 
428
    428
  • Thumbnail: Page 
429
    429
  • Thumbnail: Page 
430
    430
  • Thumbnail: Page 
431
    431
  • Thumbnail: Page 
432
    432
  • Thumbnail: Page 
433
    433
  • Thumbnail: Page 
434
    434