Cytologic screening has been widely used for detecting the cervical cancers. In this study, a semiautomatic PC-based cellular image analysis system was developed for segmenting nuclear and cytoplasmic contours and for computing morphometric and textual features to train support vector machine (SVM) classifiers to classify four different types of cells and to discriminate dysplastic from normal cells. A software program incorporating function, including image reviewing and standardized denomination of file names, was also designed to facilitate and standardize the workflow of cell analyses. Two experiments were conducted to verify the classification performance. The cross-validation results of the first experiment showed that average accuracies of 97.16% and 98.83%, respectively, for differentiating four different types of cells and in discriminating dysplastic from normal cells have been achieved using salient features (8 for four-cluster and 7 for two-cluster classifiers) selected with SVM recursive feature addition. In the second experiment, 70% (837) of the cell images were used for training and 30% (361) for testing, achieving an accuracy of 96.12% and 98.61% for four-cluster and two-cluster classifiers, respectively. The proposed system provides a feasible and effective tool in evaluating cytologic specimens.

Changes in chromosome number have a critical role in the evolution and formation of plant species. Triploids, which carry three complete sets of chromosomes, in particular produce offspring with different chromosome numbers, including diploid and tetraploid progeny, as well as a swarm of aneuploid progeny, which carry incomplete chromosome sets. In this study, we investigated the mechanisms shaping these swarms at the population level through a detailed characterization of the progeny of triploid Arabidopsis thaliana. We report that triploid meiosis predominately produced aneuploid gametes, most of which were viable. We performed reciprocal crosses between triploid and either diploid or tetraploid plants and karyotyped all surviving individuals. This allowed us to dissect the parent-of-origin (cross-direction) effects and also the effect of the dosage of the crossing partner on the inheritance of each chromosome type. Overall, our data indicate that the chromosomal composition of the swarms produced by the triploid A. thaliana were strongly influenced by selection acting against specific gamete combinations, but not necessarily associated with aneuploidy. Finally, each of the five chromosome types responded differently to this selection, suggesting the presence of dosage-sensitive factor(s) critical for viability and encoded on different chromosomes.

The maize B-chromosome consists mainly of heterochromatin and is considered to be genetically inert. However, the B-chromosome contains euchromatin that carries control elements that direct its behaviors during cell division, such as nondisjunction during the second pollen mitosis. To determine the transcriptional activity of the B-chromosome, complementary DNA-amplified fragment length polymorphism analysis was applied to five inbred maize lines with and without B-chromosomes. Six putative B-chromosome-related transcripts were identified, four of which were cloned and characterized via Southern hybridization, fluorescence in situ hybridization, and sequence comparison to further confirm their B-chromosome origin. All the analyzed B-chromosome-related transcript sequences were repetitive and showed homology to A-chromosomes. Quantitative real-time reverse transcriptase-polymerase chain reaction revealed that the B-chromosome-specific transcribed sequences B3547-179 and B3849-212 were transcribed in a B-chromosome-dosage-dependent manner. Expression of B3849-189 and B3849-147 was not specific to the B-chromosome; however, the former showed a transcriptional pattern with B-chromosome dosage compensation, and the latter displayed down-regulation of transcription due to higher B-chromosome numbers. Using four B-10L translocations, B3849-212 was mapped to the B-chromosome region that contains the nondisjunction control elements of the B-chromosome. Taken together, our results suggested that the maize B-chromosome harbors few transcriptionally active sequences and might influence the transcription of A-chromosomes.

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