Genetics, Vol. 179, 1119-1123, June 2008, Copyright © 2008
doi:10.1534/genetics.108.087726

Extraordinary Tertiary Constrictions of Tripsacum dactyloides Chromosomes: Implications for Karyotype Evolution of Polyploids Driven by Segmental Chromosome Losses

Department of Horticulture, University of Wisconsin, Madison, Wisconsin 53706

1 Corresponding author: Department of Horticulture, 1575 Linden Dr., University of Wisconsin, Madison, WI 53706.
E-mail: jjiang1{at}wisc.edu

Tripsacum dactyloides (2n = 2x = 36) is an ancient tetraploid species. Here we report that T. dactyloides chromosomes contain an extraordinary tertiary constriction, which causes a radical and distant separation of a terminal segment from the chromosome. The relationships between extraordinary tertiary constriction and segmental chromosome loss as well as karyotype evolution of polyploid species are discussed.