Overlapping DNA Segments
cM Matching on Chromosome 1
Match 1 Match 2 Non-Match
20.5
7.6

No. Part of a matching DNA segment may have a higher or lower centiMorgan (cM) value than the segment’s average. One of your matches will then have a much higher cM value for their segment.

cM Values For Three SNP Sets
SNP Set cM SNPs Chromosome Start Location Stop Location
221 0.48 100 1 82521165 82870559
222 0.26 100 1 82871547 83219651
223 0.48 100 1 83221230 83764336

This is because the recombination rate across the human autosomal genome is highly variable. For example, one matching SNP set might be 349,394 bp (base pairs) long and .48 cM while the one next to it is about the same length but is only .26 cM.