White clover is polymorphic for cyanogenesis, with both cyanogenic and acyanogenic plants occurring in nature. This chemical defense polymorphism is one of the longest-studied and best-documented examples of an adaptive polymorphism in plants. It is controlled by two independently segregating genes: Ac/ac controls the presence/absence of cyanogenic glucosides; and Li/li controls the presence/absence of their hydrolyzing enzyme, linamarase. Whereas Li is well characterized at the molecular level, Ac has remained unidentified. Here we report evidence that Ac corresponds to a gene encoding a cytochrome P450 of the CYP79D protein subfamily (CYP79D15), and we describe the apparent molecular basis of the Ac/ac polymorphism. CYP79D orthologs catalyze the first step in cyanogenic glucoside biosynthesis in other cyanogenic plant species. In white clover, Southern hybridizations indicate that CYP79D15 occurs as a single-copy gene in cyanogenic plants but is absent from the genomes of ac plants. Gene-expression analyses by RT-PCR corroborate this finding. This apparent molecular basis of the Ac/ac polymorphism parallels our previous findings for the Li/li polymorphism, which also arises through the presence/ absence of a single-copy gene. The nature of these polymorphisms may reflect white clover's evolutionary origin as an allotetraploid derived from cyanogenic and acyanogenic diploid progenitors. C YANOGENESIS (cyanide release following tissue damage) occurs in .2650 plant species, including ferns, gymnosperms, monocots, and dicots (Seigler and Brinker 1993). In its most common form, cyanogenesis involves the interaction of two compounds, cyanogenic glycosides and their hydrolyzing enzymes; these are separated in intact tissue and brought into contact with tissue disruption. White clover (Trifolium repens L., Fabaceae) is polymorphic for cyanogenesis, with both cyanogenic and acyanogenic plants occurring in natural populations (Armstrong et al. 1913;Ware 1925). This polymorphism arises through the presence/absence of both of the underlying cyanogenic components. Inheritance of cyanogenesis in white clover follows a simple Mendelian two-locus, two-allele model (Coop 1940;Melville and Doak 1940;Corkill 1942): the gene Ac/ac controls the presence/absence of cyanogenic glucosides; and the independently segregating gene Li/li controls the presence/absence of linamarase, a cyanogenic b-glucosidase (reviewed by Hughes 1991). Plants that carry at least one dominant (functional) allele at both genes (Ac and Li) are cyanogenic, while the occurrence of two nonfunctional alleles at either gene confers the acyanogenic phenotype.White clover is a common legume of fields, lawns, and pastures in mesic temperate climates. It is a native of Eurasia but has been introduced worldwide as a forage crop and lawn plant. It is a perennial and an insectpollinated, obligate outcrosser; plants also spread vegetatively by stolons. Chromosome number and genetic map data indicate that white clover is an allotetraploid (e.g., Barrett et al. 200...

No abstract

No abstract

No abstract

This paper introduces a new real-time human motion parameters capturing method using Kinect. It consists of five modules. First, the hybrid action type classifier categories human body motion into four different action types. Second, for each action type, there is a body part (BP) classifier which segments the human silhouette into 16 BP regions of which the centroids become the BP joints. These BP joints are linked to represent the human body skeleton. Third, an action type validation process verifies the identified action type. Fourth, the partial occlusion recovery method relocates the occluded BP joints. Fifth, the offset compensation process fine tunes the positions of BP joints and then validates the compensation results. The major contributions of this paper are hybrid action type classification and correction, offset compensation, and partial occlusion recovery. The experimental results show that this method can estimate human upper limb motion parameters in real time accurately and effectively.