Table 2. Nucleotide sequence variations within the MSH2 gene sequence of 50 T. cruzi isolates from the United States compared to reference strains.

Genotype/Isolate	Nucleotide Position
	71	97	109	172	244	351	367	373	403	404	460	478	490	500	634	645	658	735	750	775	816
TcI Reference strain (Silvio X10 cl1)	C	A	G	A	C	T	A	G	G	G	A	T	C	A	T	C	A	C	A	G	A
TcI – 17 US sequences*	•	•	•	•	•	A	•	•	•	•	•	•	•	•	•	•	•	•	•	•	•
TcI-USA Opossum	•	•	•	•	•	A	•	•	•	•	•	•	•	•	•	•	•	•	•	•	G
TcI-93070103P cl2	•	•	•	•	•	A	•	•	•	•	•	Y	•	•	Y	S	•	•	T	•	•
Amino acid change						V→D										S→C

Genotype of each isolate precedes the isolate name. Nucleotide positions correspond to sites from SilvioX10 cl1 (Genbank AY540739). Dots represent nucleotide site identical to reference strain (either Silvio X10 cl1 for TcI or CANIII cl1 for TcIV).

^*The following 17 US TcI sequences were identical: Human isolates (TC CC, CA R, TC California), domestic dogs (USA Dog Y), Virginia opossums (92101601P cl2, 93041401P cl2, FH4, FL Opo 2, FL Opo 3, FL Opo 15, Opossum 1970), armadillos (Armadillo 1973, USA Armadillo), triatomine bugs (Florida C1F8, Florida), and raccoons (93053103R cl3, FL Rac 13).

^†The following 23 US TcIV sequences were identical: Raccoons (FL Rac 9, 92122102R, 93071502R cl2, 93040701R cl1, 93072805R cl3, FL Rac 15, FL Rac 46, FL Rac 5, GA Rac 134, GA Rac 143, GA Rac 69, Maryland Rac, STC 35R), domestic dogs (Samantha Dog, Caesar Dog, Dog Theis, OK Dog, Smokey), ring-tailed lemurs (Clarence, Meg), rhesus macaque (Texas Theis), striped skunk (GA Sk 1), and armadillo (GA Arm 20).