Abstract:
Apparatus is disclosed in which a flat, transparent, plastic template bears a combination of inscribed marks and apertures to cooperate with each other so as to enable a user to readily draw two-dimensional depictions of circular and linear plasmid deoxyribonucleic acid (DNA). The template further cooperates with additional apertures for the forming of indicators and markings commonly incorporated in drawings of plasmid DNA.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     Not applicable. 
     BACKGROUND—FIELD OF INVENTION 
     This invention relates to drafting instruments and pertains to templates which assist a scientist in drawing two-dimensional representations of plasmid deoxyribonucleic acid (DNA). 
     BACKGROUND—DESCRIPTION OF PRIOR ART 
     Drawings of plasmid DNA are commonly performed by scientists in the field of biochemistry and related disciplines. Depictions of both circular and linear forms of plasmid DNA are usually drawn free hand with the assistance of geometrical templates or compasses. Many separate, time-consuming drawing steps are required to render satisfactory results. Moreover, available hand-held drafting instruments do not provide guides for specific features needed for the drawing of plasmid DNA, such as curved arrows. 
     Thereafter, inventors created computer-aided drafting software as a means to present plasmid DNA information. However, these software applications are relatively expensive, require considerable amounts of operational instruction, and do not address the need for hand drawing, simplicity, and portability. 
     Accordingly, one object of this invention is to achieve a device which facilitates the drawing of both circular and linear forms of plasmid DNA in a unitary design which is mechanically simple and easy to use. 
     SUMMARY 
     In accordance with the preferred embodiment of the invention, a transparent, plastic template cooperates with indicia marked on its surface to facilitate drawing of a variety of circular and linear plasmid DNA forms. 
     OBJECTS AND ADVANTAGES 
     Accordingly, an object of the present invention is to provide a simple template for forming curved arrows, curved bars, straight arrows, and straight bars and for describing circles and straight lines to facilitate the construction of plasmid DNA drawings. 
     Further objects and advantages are to provide a plasmid DNA drawing template that can be quickly and conveniently used without the need for free hand or computer-aided drafting. Still further objects, advantages, and salient features will become more apparent from a consideration of the ensuing description and drawing. 
    
    
     DRAWING FIGURES 
     FIG. 1 is a front elevation view of the overall structure of the invention. 
    
    
     DESCRIPTION 
     FIG.  1 —Preferred Embodiment 
     Referring to FIG. 1, a flat plastic, preferably transparent, unitary panel  10  is disclosed which comprises a template  11  and a plurality of openings defined by edges  13 ,  14 ,  15 ,  16 ,  17 ,  18 ,  19 ,  20 ,  21 , and  22 . 
     In the embodiment disclosed, the edge  13  defines a large circular opening. Moreover, the edge  13  is marked with indicia  31  distributed preferably every 18 degrees. 
     The edges  14  and  15  define curved arrows whose central radii matches the radius of the large circle defined by the edge  13 . The edges  14  and  15  are marked with indicia  32  and  33 , respectively, distributed preferably every 18 degrees. Moreover, the edges  14  and  15  are marked with indicia  36  and  37 , respectively, at their radial centers. 
     The edges  16  and  17  define straight arrows whose lateral centers are marked by indicia  38  and  39 , respectively. Moreover, the edges  16  and  17  are marked with indicia  34  and  35 , respectively, distributed preferably every 1 centimeter. 
     The edges  18 ,  19 ,  20 , and  21  define an arrow, a bent arrow, a half arrow, and a curved arrowhead, respectively. The edge  22  defines a small circle. The edges  23  and  24  define a 90-degree curve and are marked by indicia  40 . 
     Finally, indicia  41  are inscribed along the edge  25  of the template  11 . As shown in FIG. 1, the indicia  41  are arranged to display metric dimensions. 
     Operation—FIG. 1 
     The manner of using the template for drawing plasmid DNA is similar to that of other drafting instruments for geometrical shapes, but with some important differences. Namely, the user first describes a large circle defined by the edge  13 . The circle acts as the backbone of the plasmid DNA. Curved arrows or curved bars defined by the edges  14  and  15  are then traced over the large circle. Indicia  32  or  33  and  36  or  37 , respectively, in cooperation with the drawn large circle allows the user to readily create a curved arrow or curved bar of a predetermined radial distance that is aligned on top of the drawn large circle. Drawing of arrows of opposite direction is facilitated by simply turning the template over. The curved arrows or curved bars represent plasmid-borne genes or other nucleic acid regulatory or structural sequences. 
     Similarly, straight arrows or straight bars defined by the edges  16  and  17  can be traced over a straight line. Indicia  34  or  35  and  38  or  39 , respectively, in cooperation with a drawn straight line enables a user to readily draw a straight arrow or straight bar of a predetermined length that is aligned on top of the drawn straight line. The straight arrows or straight bars are linear representations of embedded genes or other nucleic acid regulatory or structural sequences. 
     The edges  18 ,  19 ,  20 , and  21  are used to draw various forms of arrows or arrowheads in the manifestation of the plasmid DNA diagram to serve as indicators of gene transcription, replication, primer position, and other relevant markers. The edge  20  is used to trace a small circle for the depiction of additional plasmid traits. 
     The edge  25  in cooperation with indicia  41  serves as a straightedge for drawing lines of a desired length. 
     Finally, the edges  23  and  24 , in cooperation with indicia  40 , allows the user to create right-angled lines. This is used to help display augmentations, such as inserted DNA, to the backbone of the plasmid DNA drawing. 
     Conclusion, Ramifications, and Scope 
     In conclusion, a novel template has been disclosed and described in which a clear, plastic template bears a combination of inscribed marks and apertures adapted to cooperate with each other so as to enable a user to readily draw two-dimensional depictions of plasmid DNA. The result is a simple drafting tool. 
     Furthermore, the drawing template for plasmid DNA has the additional advantages in that it can be used with a variety of writing implements and surfaces. For example, the template can facilitate the drawing of plasmid DNA with a felt marker onto plastic transparencies for use in overhead projections. 
     While the above description contains many specificities, these should not be construed as limitations on the scope of the invention, it is merely representative of the principals of the invention and it is anticipated and expected that those skilled in the art will readily recognize and utilize other embodiments falling within the scope of the invention. 
     Accordingly, the scope of the invention should be determined not by the embodiment illustrated, but by the appended claims and their legal equivalents.