But the SPECIFIC PATTERNS -- and btw, mutiple, nested heirachies of patterns; and patterns that persist even if you look only at synonomous mutations (that don't change the amino acid coded for) or other factors with no functional impact -- DO imply common ancestry, and cannot be explained by any other cause suggested to date (excepting intentional deception by a creating agent).
See the brief exposition in #247 and please answer for us the questions that the author asks of antievolutionists.
I might add that many mapmakers put tiny, deliberate errors in their products to catch copyright violaters. So do software makers.
The inclusion of nonfunctional errors and inclusions is the best known way of tracking lineage.
If this is not a valid way of reasoning, then a lot of prisoners will be going free.