U.S. Department of Agriculture: Agricultural Research Service, Lincoln, Nebraska
Document Type
Article
Date of this Version
1999
Citation
Crop Sci. 39:661-667
Abstract
Nuclear DNA content was determined by flow cytometry for an array of perennial species of the Triticeae (Poaceae) which characterize the tribe and are representative of the genomes of the Triticeae. The mean nuclear DNA content expressed on a diploid basis (DNA pg/2C) for the diploid genomes (in parentheses) were as follows: Agropyron (PP) 13.9 pg, Pseudoroegneria (StSt) 8.8 pg, Hordeum (HH) 9.5 pg, Psathyrostachys (NsNs) 16.7 pg, and Thinopyrum genomes (EeEe) 14.9 pg and (EeEe) 12.0 pg. The YY genome in Elymus was determined by difference to be 9.3 pg. The unknown or XmXm genome or genomes in Leymus could have DNA contents that range from 2.7 to 7.7 pg/2C. There were significant differences in DNA content of species with similar diploid genomes. There were also significant differences in nuclear DNA content among polyploid species with the same genomes. In general, the nuclear DNA content of the polyploid species of the Triticeae were similar to the expected DNA contents on the basis of previous genomic classifications. However, in some allopolyploid genera such as Thinopyrum and Pascopyrum, the nuclear DNA content of some species was less than expected on the basis of summation of the DNA of constituent genomes. The results indicate that gain or loss of nuclear DNA has occurred during the evolution of the perennial Triticeae and was probably a part of speciation.
Comments
U.S. government work