- Add the first person with Male, Female or Unknown on the toolbar. This is usually the person the pedigree is for, so switch on Proband in the panel that opens.
- Build out from them. With someone selected, Add a relative puts in a partner, son, daughter, parents, brother or sister, already joined up, and lays the pedigree out again to make room. Older and Younger move a person, with their family, along their row of brothers and sisters, which runs from the oldest on the left.
- Join people yourself with Partners, Child and Twins on the toolbar. Partners: click two people. Child: click a relationship line, then the child. Twins: choose identical, non-identical or not known in the panel, then click two children of the same couple; for triplets or more, link each of the others to one already linked.
- Describe each person in the panel: notes under the symbol (name, age, diagnoses and the age at diagnosis), deceased, shading for anyone affected, and a mark inside the symbol for carriers, pregnancies, donors, gestational carriers or a number of people.
- Click a line to change it. A relationship line can be marked consanguineous or separated, and you can add the couple's children from there, including a pregnancy loss, no children or infertility. A line of descent can be dashed for adoption.
- Tidy lays the whole pedigree out again: generations in rows, couples side by side, brothers and sisters together under their parents in the order you drew them, and as few crossing lines as possible. Undo puts your own layout back.
- Save and export from File: a picture (PNG, or SVG for documents and posters) or a pedigree file (.json) that you can open again later. The pedigree you are working on is also kept in this browser until you clear it.
The toolbar
Moving around
Drag a person to move them. Dragging moves their whole connected family unless Move one person at a time is switched on under File. Drag the background to move the view, scroll or pinch to zoom, and use the button at the bottom right to fit everything in.
Colours and the key
Use a different shading colour, or halves, thirds and quarters, for each condition. Key adds a box listing the colours in use; type what each one means into it. Under File, Long entries in the key says whether a long entry widens the key, keeping each entry on one line, or wraps onto more lines; when it wraps, drag the key's right edge to make it wider or narrower. The key is included when you export, just as it looks.
These are the symbols of the standard pedigree nomenclature (Bennett et al., 2008 and 2022, as corrected in 2025), drawn as Pedigree Studio draws them. Write ages, diagnoses and test results under the symbol with Notes.
| Ctrl + Z | Undo |
| Ctrl + Y or Ctrl + Shift + Z | Redo |
| Delete or Backspace | Delete what is selected |
| Shift + click | Select several people, or several lines |
| Ctrl + A | Select everyone |
| Esc | Back to Select, and clear the selection; closes the help or a menu first |
| Arrow keys | Nudge the selection by 1 pixel, or 10 with Shift, when Move one person at a time is on |
| Double-click a text label | Edit its text |
| Double-click the label under a symbol | Type your own label, when numbering is set to Own |
| Drag the background | Move the view |
| Scroll, or pinch | Zoom |
| ? | Open this help |
On a Mac, use ⌘ in place of Ctrl.
Without a connection
Open Pedigree Studio once from its website, pedigreestudio.xyz, and it will open there again without a connection. To keep it as an app, install it: choose Install in the browser's menu (Chrome, Edge) or Add to Home Screen (Safari on an iPhone or iPad, Chrome on Android). Or save the page itself: it is one file, which opens in a browser from your computer or a USB stick.
Your data
Pedigree Studio runs entirely in your browser: nothing you draw is sent anywhere, and the page itself makes no network requests. Opened from its website, the browser also keeps a copy of the Studio so that it opens without a connection, and fetches a newer copy when there is one; those requests fetch only the Studio's own files. The pedigree you are working on is kept in this browser's own storage so that it is still here next time; Clear the canvas under File removes it, from Undo as well, so it cannot be brought back. Exported pictures and pedigree files are made on this device.
Citing Pedigree Studio
Hearn TJ. PedigreeStudio [software]. Zenodo. doi:10.5281/zenodo.20209376. Source code and issues: github.com/comparativechrono/PedigreeStudio (MIT licence).
Pedigree nomenclature
- Bennett RL, Steinhaus KA, Uhrich SB, O'Sullivan CK, Resta RG, Lochner-Doyle D, Markel DS, Vincent V, Hamanishi J. Recommendations for standardized human pedigree nomenclature. Am J Hum Genet. 1995;56(3):745–752. PMID 7887430.
- Bennett RL, French KS, Resta RG, Doyle DL. Standardized human pedigree nomenclature: update and assessment of the recommendations of the National Society of Genetic Counselors. J Genet Couns. 2008;17(5):424–433. doi:10.1007/s10897-008-9169-9.
- Bennett RL, French KS, Resta RG, Austin J. Practice resource-focused revision: Standardized pedigree nomenclature update centered on sex and gender inclusivity: a practice resource of the National Society of Genetic Counselors. J Genet Couns. 2022;31(6):1238–1248. doi:10.1002/jgc4.1621.
- Steinhaus French K, Bennett R, Resta R. Correction to: Practice resource-focused revision: Standardized pedigree nomenclature update centered on sex and gender inclusivity: a practice resource of the National Society of Genetic Counselors. J Genet Couns. 2025;34(2):e2020. doi:10.1002/jgc4.2020.
- Resta RG, French KS, Bennett RL, Austin J. Both sides now: changing a long-standing pedigree tradition of men on the left and women on the right. J Genet Couns. 2023;32(3):530–531. doi:10.1002/jgc4.1662.
How Tidy works
Tidy treats the pedigree as a layered drawing, the approach introduced by Sugiyama et al. (1981). It puts each person in a generation by the network simplex method of Gansner et al. (1993). It orders each row to keep families together with as few crossing lines as possible, using the barycentre method of Sugiyama et al. and sifting (Matuszewski et al., 1999). It then finds the positions that centre children under their parents and keep lines straight, by solving a small optimisation problem with FISTA (Beck and Teboulle, 2009), using the adaptive restarts of O'Donoghue and Candès (2015).
- Sugiyama K, Tagawa S, Toda M. Methods for visual understanding of hierarchical system structures. IEEE Trans Syst Man Cybern. 1981;11(2):109–125. doi:10.1109/TSMC.1981.4308636.
- Gansner ER, Koutsofios E, North SC, Vo KP. A technique for drawing directed graphs. IEEE Trans Softw Eng. 1993;19(3):214–230. doi:10.1109/32.221135.
- Matuszewski C, Schönfeld R, Molitor P. Using sifting for k-layer straightline crossing minimization. In: Graph Drawing (GD 1999). Lecture Notes in Computer Science, vol 1731. Springer; 1999. p. 217–224. doi:10.1007/3-540-46648-7_22.
- Beck A, Teboulle M. A fast iterative shrinkage-thresholding algorithm for linear inverse problems. SIAM J Imaging Sci. 2009;2(1):183–202. doi:10.1137/080716542.
- O'Donoghue B, Candès E. Adaptive restart for accelerated gradient schemes. Found Comput Math. 2015;15(3):715–732. doi:10.1007/s10208-013-9150-3.