# Plasmid map maker

> Draw a circular or linear plasmid map from features and restriction sites, or import a GenBank file. Labels never overlap; download SVG or PNG. Free.

URL: https://www.labcanvas.com/tools/plasmid-map-maker

Enter the plasmid name and size in bp, list the features (name, start, end, strand and type: gene, promoter, origin, resistance marker, MCS or terminator) and any restriction sites, and the tool draws a circular plasmid map with direction arrows, bp tick marks and labels placed outside the circle so they never overlap, plus an optional linear map. You can import the features from a GenBank file (including complement() and join() locations) and find unique restriction sites in the sequence. Download the map as SVG for figures or as a high-resolution PNG. It opens with pUC19 (2686 bp).

## Quick answer

- **What it does:** Draws a circular (and linear) plasmid map from a list of features and restriction sites, or from a GenBank file, as SVG or PNG.
- **Formula:** Angle = 360° × (position − 1) / plasmid size, clockwise from the top; forward (+) features point clockwise, reverse (complement) features anticlockwise.
- **Example:** pUC19 (2686 bp): AmpR (bla) at complement(1626..2486) spans 861 bp, an arc of 360° × 861 / 2686 = 115.4°; the MCS holds EcoRI at 396 and HindIII at 447.

Free, in the browser, no account needed. Updated 2026-10-19.

## Features

- Circular map with curved arrows for forward and reverse features, bp tick marks and the name and size in the centre
- Optional linear map of the same plasmid
- Conventional colours: genes blue, promoters green, origins yellow, resistance markers red, MCS purple, terminators brown
- Labels outside the circle, pushed apart so they never overlap, with leader lines; overlapping features go on separate rings
- Restriction sites by name and position, or found in a pasted sequence (24 common enzymes; unique or 1–2 cutters)
- GenBank import: LOCUS size, CDS/gene, promoter, rep_origin, terminator and MCS features, complement(), join() across the origin, <1..>200
- Download SVG (editable in Illustrator, Inkscape, PowerPoint) or PNG at 3× resolution; nothing is uploaded

## How to use it

1. **Set the plasmid**: Type the name and total size in bp, or import a GenBank file to fill everything in.
2. **Add features and sites**: List each feature with its start, end, strand and type; add restriction sites by hand or find them in the sequence.
3. **Download**: Check the circular and linear maps and download SVG or PNG for your figure, thesis or slide.

## At a glance

| | |
| --- | --- |
| Input | Size, features (start, end, strand, type), restriction sites; or a GenBank file |
| Maps | Circular with tick marks; optional linear |
| Layout | Overlapping features on separate rings; non-overlapping labels with leader lines |
| Restriction search | 24 common enzymes on the circular sequence; unique or 1–2 cutters |
| Export | SVG and PNG (3×) |
| Example | pUC19, 2686 bp (NEB annotation) |

## How it works

**Coordinates.** Positions are 1-based and inclusive, as in GenBank. Position \(p\) of a plasmid of \(N\) bp sits at angle \(\theta = 360^\circ \times (p - 1) / N\), clockwise from 12 o’clock, so base 1 is at the top. A feature from \(s\) to \(e\) covers \(e - s + 1\) bp; when \(s \gt e\) it crosses the origin and covers \(N - s + 1 + e\) bp. Forward-strand features point clockwise and reverse-strand (complement) features anticlockwise; an MCS or other feature without a direction is drawn as a plain band.

**Layout.** Features that overlap are placed on separate rings (longest first, each on the innermost free ring). Labels are split into the right and left halves of the circle, sorted by the height of their anchor, then pushed apart to at least one line of text and drawn on a larger circle with a leader line to the feature or site. Tick marks use a step of \(1, 2, 2.5 \text{ or } 5 \times 10^k\) bp giving about 12 ticks.

**GenBank import.** The size comes from the LOCUS line (or the ORIGIN sequence). From the FEATURES table the tool reads CDS and gene (as genes, or resistance markers when the name or note mentions bla/AmpR, kan/neo, cat, tet, hph, zeo, bsd, puro or spec), promoter, rep_origin, terminator, regulatory promoters and terminators, and misc_feature entries labelled as an MCS or polylinker. A feature is named from /label, /gene, /product or /note. complement() gives the reverse strand; for join() the outermost positions are used, and a join that runs past the end (join(2600..2686,1..40)) becomes a feature crossing the origin. Source, primer_bind and −10/−35 boxes are left out to keep the map readable.

**Restriction sites.** The sequence is searched as a circle (sites spanning the origin are found) for 24 palindromic 6- and 8-base recognition sequences; the position given is the first base of the recognition site on the top strand.

Sources: pUC19 sequence and feature coordinates from New England Biolabs’ pUC19 GenBank file ([neb.com, pUC19 GenBank](https://www.neb.com/-/media/nebus/page-images/tools-and-resources/interactive-tools/dna-sequences-and-maps/text-documents/puc19gbk.txt)), identical in sequence to GenBank L09137; Yanisch-Perron C, Vieira J, Messing J. Improved M13 phage cloning vectors and host strains: nucleotide sequences of the M13mp18 and pUC19 vectors. *Gene* 1985;33:103–119, [doi:10.1016/0378-1119(85)90120-9](https://doi.org/10.1016/0378-1119(85)90120-9).

## Worked example: the pUC19 map

The tool opens with **pUC19**, 2686 bp, with the features annotated by New England Biolabs (the promoters span NEB’s −35 to −10 boxes):

| Feature | Location | Length | Arc | Type |
| --- | --- | --- | --- | --- |
| lacZα | complement(146..469) | 324 bp | 43.4° | Gene |
| MCS | 396..452 | 57 bp | 7.6° | MCS |
| lac promoter | complement(514..543) | 30 bp | 4.0° | Promoter |
| ori (pMB1) | complement(867..1455) | 589 bp | 78.9° | Origin |
| AmpR (bla) | complement(1626..2486) | 861 bp | 115.4° | Resistance |
| AmpR promoter | complement(2530..2556) | 27 bp | 3.6° | Promoter |

Every feature is on the reverse strand, so every arrow points anticlockwise. The MCS lies inside lacZα, so it goes on a second ring. Finding unique cutters in the sequence gives the polylinker sites EcoRI 396, SacI 402, KpnI 408, SmaI 412, BamHI 417, XbaI 423, SalI 429, PstI 435, SphI 441 and HindIII 447 (ten labels within 51 bp, spread apart by the label layout), plus NdeI 183, ScaI 2177 and AatII 2617 (XmaI cuts at the same site as SmaI). PvuI and PvuII cut twice.

**Arc by hand.** AmpR runs from 1626 to 2486: \(2486 - 1626 + 1 = 861\) bp, and \(360^\circ \times 861 / 2686 = 115.4^\circ\). Its start sits at \(360^\circ \times 1625 / 2686 = 217.8^\circ\) clockwise from the top.

**A feature across the origin.** In a 5000 bp plasmid, a gene from 4800 to 300 covers \(5000 - 4800 + 1 + 300 = 501\) bp; in GenBank it is written join(4800..5000,1..300).

## Questions

### How do I make a plasmid map?

Enter the plasmid size and each feature’s start, end, strand and type, or import a GenBank file from Addgene, SnapGene or NCBI. The tool draws the circular map with arrows and labels; download it as SVG or PNG.

### How do I import a GenBank file?

Drop the .gb or .gbk file on the import box, or paste its text. The size, features and sequence are read, and the unique restriction sites are found in the sequence. Edit the feature table afterwards to rename or remove features.

### What do the colours on a plasmid map mean?

There is no fixed standard, but by convention genes (coding sequences) are blue, promoters green, origins of replication yellow, antibiotic resistance genes red and the multiple cloning site is shown separately. Change the type of a feature to change its colour.

### What does complement mean in a GenBank feature?

complement(1626..2486) means the feature is on the reverse strand between those positions, so it is read anticlockwise on the map. The AmpR gene of pUC19 is an example.

### How do I show a feature that crosses the origin?

Give a start greater than the end, for example start 4800 and end 300 in a 5000 bp plasmid. In GenBank such a feature is written join(4800..5000,1..300), which the importer reads the same way.

### What restriction sites are in the pUC19 MCS?

From the NEB sequence: EcoRI 396, SacI 402, KpnI 408, SmaI/XmaI 412, BamHI 417, XbaI 423, SalI 429, PstI 435, SphI 441 and HindIII 447 (first base of each recognition site). All of these cut pUC19 once.

### Can I edit the map in Illustrator or PowerPoint?

Yes. Download the SVG: every arc, line and label is a separate vector element with real text, so you can recolour or move them. PowerPoint (Microsoft 365) inserts SVG directly.