Mystery Monday: Her Voyage, Part V

Where did she go? And how did she become
This being we confronted now? A test
Of DNA proved we were sisters. From
Her sample, too, we found that she, at best,
Had telomeres like any toddler child 

Might boast. How had this happened? She could not

Explain it. She had always, since the wild
Unconquered isle had first felt the hard trot
Of man and horse, dwelt here. The locals called
Her Grammy and they left her quite alone,
Unless someone, like she, felt strangely called
By forces both uncanny and unknown.
Such folk might visit her, and she would take
Their visions from them, gently, with a shake.