Genetic lineage of grass.

Hi CarbonRobot

It's likely, but as a property owner myself, it's likely that fresh seeds have been added over the years, leading to healthier breeds that have competed with the original stuff. For example, I top off my lawn with new seeds yearly. I also have replaced large areas of my land with new sod. Thus, it's only unlikely given that grass is so often replaced due to unnatural reasons. HOWEVER, if the grass in your yard has been able to grow and propagate naturally over the years without significant disruptions, then there is a good chance that it has genetic continuity with the grass from 50 years ago.