re: Many food and agricultural varieties going "extinct"?

quote:

---

Everything I've read has lead me to believe it's not the same variety but a copy.

---

What do you mean by a copy? Every seed is a new generation of a plant, so they're all copies. Each generation shows genetic differentiation from the parent plant, so unless it's a vegetative clone (aka a "cutting"), the seeds may differ from the ancestor generations over time.

Not sure what you're reading...but corn seeds are viable for an alarmingly long time if kept dry. Modern corn (zea mays) is descended from teosinte, which still grows wild in Mexico. The Anasazi grew sweet corn; here's a source for those seeds: LINK

Again, the stuff planted in 1,000 acre + stands across the Midwest is largely sown from modern seed. But that doesn't mean the other varieties are extinct.