The diagram on the left is a pedigree of a mother (AU-3104), father (AU-3103), daughter (AU-3101) and son with autism (AU-3101). Female symbols are circles and males are squares. Unaffected individuals are open symbols and the autistic son is a shaded symbol. The double line connecting the two parents indicates that they are related. Each horizontal bar represents a map of single nucleotide polymorphisms (SNPs) along one arm of chromosome 3 of the family members. Red and blue vertical stripes indicate homozygous SNPs for either one of two alleles, yellow stripes represent heterozygous SNPs, and white gaps represent genetic deletions. The horizontal black line demarcates a region of with a pattern of homozygosity not found in the autistic boy’s parents or sister.
The accompanying downloadable Educator Materials PDF includes background information, graph interpretation and discussion questions. The Student Handout includes the image and background information.
Figure 1A from:
Morrow, Eric M., et al. Identifying Autism Loci and Genes by Tracing Recent Shared Ancestry. 2008. Science 321(5886): 218-223.