The ( low-copy) nematode resistance source harbors a copia-family retrotransposon within the encoded α-SNAP gene.

Soybean growers widely use the Resistance to 1 () locus to reduce yield losses caused by soybean cyst nematode (SCN). is a tandemly repeated four gene block. Two classes of SCN resistance-conferring haplotypes are recognized: ("Peking-type," low-copy number, three or fewer repeats) and ("PI 88788-type," high-copy number, four or more repeats).