This document is meant to accompany FASTLINK, version 2.0 and beyond. It describes some aspects of pedigree traversal in FASTLINK. It is primarily intended for computer scientists and experts in linkage analysis who may wish to modify the LINKAGE or FASTLINK code in various ways.

Everything written in this document also applies to LINKAGE. This document is based on my own approach to understanding pedigree traversal and my own terminology. So far as I know, overlaps with other descriptions of pedigree traversal are largely incidental. Thanks to Meg Gelder Ehm (Rice University), Sandeep Gupta (Rice University), and Prof. Daniel Weeks (University of Pittsburgh) for asking enough questions about pedigree traversal to motivate me to write this document.

Thanks to Darrell Root (Oregon Health Sciences University) for contributing PostScript files with the first 3 sample pedigrees shown below. His pedigrees were drawn with:

PedDraw v.4.4r2 by Paul Mamelka, Bennet Dyke, and Jean MacCleur, Department of Genetics, Southwest Foundation for Biomedical Research, 1993.

Thanks to Prof. Elizabeth Thompson (University of Washington) for contributing a PostScript file with the last sample pedigree shown below. Her pedigree was drawn with psdraw, for which the reference is:

Geyer, C. J., "Software for calculating gene survival and multigene descent probabilities and for pedigree manipulation and drawing," Technical Report No. 153, Department of Statistics, University of Washington, 1988.

This document describes pedigree traversal for loopless pedigrees. The issue of loops is dealt with in the accompanying document Loops in FASTLINK. This document should be read before the loops document.

• Why Traverse the Pedigree
• Nuclear Family Graph
• Edge Labels
• Traversal Order
• Examples