In this article, we report our investigation of the
relationship between phenotype and karyotype in populations
of aneuploid Arabidopsis thaliana plants. All simple
trisomics of A. thaliana have been previously isolated
and phenotypically characterized (Steinitz-Sears 1962;
Lee-Chen and Steinitz-Sears 1967; Steinitz-Sears
and Lee-Chen 1970; Koornneef and Van der Veen
1983), demonstrating that they are tolerated in A. thaliana.
We previously reported that aneuploid swarms—
populations of aneuploid individuals of varying aneuploid
karyotypes—could be obtained from the progeny of
triploid A. thaliana individuals (Henry et al. 2005, 2009).
Using a combination of a quantitative PCR-basedmethod
and flow cytometry, we were able to derive the full aneuploid
karyotype of each of these individuals (Henry et al.
2006).We further crossed triploid A. thaliana to diploid or
tetraploid individuals and demonstrated that at least 44 of
the 60 possible aneuploid karyotypes that could result
from these crosses (aneuploid individuals carrying between
11 and 19 chromosomes) were viable and successfully
produced adult plants. Taken together, these
populations and methods make it possible to explore the
basis of aneuploid syndromes in A. thaliana. In this study,
we were able to phenotypically characterize at least one
individual from 25 different aneuploid karyotypes falling
between diploidy and tetraploidy. We demonstrated that
specific phenotypes are affected by the dosage of specific
chromosome types. The effect of the dosage of specific
chromosome types on traits was additive and could be
used to predict the observed phenotype. The availability
of multiple generations of aneuploid and euploid individuals
allowed us to investigate potential long-term
effects of aneuploidy as well as parent-of-origin effects
on aneuploid phenotypes.