Annals of Botany 85: 351-357, 2000
© 2000 Annals of Botany Company
Allium cepa L. Cultivars from Four Continents Compared by Flow Cytometry show Nuclear DNA Constancy
Royal Botanic Gardens Kew, Richmond, Surrey, TW9 3DS, UK Departments of Entomology and Soil and Crop Science, Texas A&M University, College Station, Texas, 77843-2474, USA
Received: 27 August 1999 ; Returned for revision: 23 September 1999 . Accepted: 11 November 1999
In 1965 Van't Hof estimated the nuclear DNA amount of an unidentified Allium cepa L. cultivar as 2C = 33.55 pg (Experimental Cell Research39: 8–58). This value has been adopted by common usage as the main calibration standard for angiosperm DNA C-value estimations. However, different cultivars have been used while assuming species DNA C-value constancy. Surprisingly this assumption has never been tested. A. cepa is an outbreeder with telomeric heterochromatic segments, so intraspecific variation in C-value, possibly correlated with environmental factors as seen in Zea mays L., might be expected. We used laser flow cytometry to compare nuclear DNA amounts in roots of six A. cepa cultivars used as calibration standards or from different environments. Tissues from one cultivar, or similar volumes of tissue from two cultivars, were run and the variance between nuclei in 2C peaks compared. Only one shoulderless 2C peak was seen for all pairs of co-chopped cultivars. Thus, no large differences in C-value between cultivars from different environments were found. Moreover, comparing cultivars run singly or as pairs showed no evidence for increased variation in 2C peaks in the latter, and hence of critical differences in DNA amounts between ‘Ailsa Craig’ and another cultivar. Such variation was insufficient to make their use as alternative calibration standards, or the practice of imputing Van't Hof's original C-value estimate to them, unacceptable for most practical purposes. Given the mechanisms known which can generate genome size variation, the degree of constancy in DNA C-value found seems remarkable. Copyright 2000 Annals of Botany Company
Allium cepa, onion cultivars, calibration standards, DNA C-value constancy, flow cytometry
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  B. HENDRIX and J. McD. STEWART Estimation of the Nuclear DNA Content of Gossypium Species Ann. Bot., April 1, 2005; 95(5): 789 - 797. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. DOLEZEL and J. BARTOS Plant DNA Flow Cytometry and Estimation of Nuclear Genome Size Ann. Bot., January 1, 2005; 95(1): 99 - 110. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. R. GREGORY The C-value Enigma in Plants and Animals: A Review of Parallels and an Appeal for Partnership Ann. Bot., January 1, 2005; 95(1): 133 - 146. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. S. JOHNSTON, A. E. PEPPER, A. E. HALL, Z. J. CHEN, G. HODNETT, J. DRABEK, R. LOPEZ, and H. J. PRICE Evolution of Genome Size in Brassicaceae Ann. Bot., January 1, 2005; 95(1): 229 - 235. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Macroevolution, hierarchy theory, and the C-value enigma Paleobiology, June 1, 2004; 30(2): 179 - 202.
|
|
|
|
 |
|
 A. L. Rayburn, D. P. Biradar, R. L. Nelson, R. McCloskey, and K. M. Yeater Documenting Intraspecfic Genome Size Variation in Soybean Crop Sci., January 1, 2004; 44(1): 261 - 264. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. NAGANOWSKA, B. WOLKO, E. SLIWINSKA, and Z. KACZMAREK Nuclear DNA Content Variation and Species Relationships in the Genus Lupinus (Fabaceae) Ann. Bot., September 1, 2003; 92(3): 349 - 355. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. A. MOSCONE, M. BARANYI, I. EBERT, J. GREILHUBER, F. EHRENDORFER, and A. T. HUNZIKER Analysis of Nuclear DNA Content in Capsicum (Solanaceae) by Flow Cytometry and Feulgen Densitometry Ann. Bot., July 1, 2003; 92(1): 21 - 29. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. D. BENNETT, I. J. LEITCH, H. J. PRICE, and J. S. JOHNSTON Comparisons with Caenorhabditis (~100 Mb) and Drosophila (~175 Mb) Using Flow Cytometry Show Genome Size in Arabidopsis to be ~157 Mb and thus ~25 % Larger than the Arabidopsis Genome Initiative Estimate of ~125 Mb Ann. Bot., April 1, 2003; 91(5): 547 - 557. [Abstract] [Full Text] [PDF]
|
|