Genetics · Module 18 · Human inheritance and risk

Human Inheritance Lab

Build and analyse family pedigrees and watch every mode of inheritance be tested against them; run Bayesian risk step by step; practise mode, carrier, Hardy-Weinberg and Bayesian problems with animated worked solutions; match conditions and pedigree clues to patterns; and work through three counseling families. All families are fictional. Nothing here is graded.

Part 1: Pedigree Builder and Analyzer

Affected (filled)Unaffected (open) Moving dot: mutant allele passed onRed ring with ! : contradiction for the chosen modeGlow: selected person
How well each mode of inheritance fits this pedigree
ModeVerdictRelative fitWhy

How the analyzer works: for each mode it searches every possible set of genotypes for the people shown and asks whether Mendelian transmission can produce exactly these affected and unaffected people. "Ruled out" means no genotypes work, and the contradicting people are listed. Relative fit compares the modes that do work, assuming the variant is rare (allele frequency 1%), each mode equally likely beforehand, 80% penetrance when that option is on and a new mutation rate of 1 in 10,000 per transmission when that option is on. Mitochondrial inheritance is treated as homoplasmic. Partners who married in are assumed unrelated.

Bayesian risk calculator