Jennifer Hartswell is amongst the last group of live-aboards to be transported to the New York Mothership. She has uniquely high immune system, unlike anyone else on Earth that the Visitors have tested. Her mother, Melissa, had reservations over the live-aboard program, because she originally thought that she had to leave Jennifer on Earth. Anna arranges to meet Melissa to convince her to move to the Mothership with Jennifer, telling her that Anna has her own daughter, precisely Jennifer's age, by the name of Amy (which happens to be Melissa's mother's name - Anna must have done some background research).
Jennifer is the last of the live-aboards to have her DNA extracted. Anna informs Thomas to ask Joshua to begin harvesting her DNA almost immediately upon her arrival on the New York Mothership. The combination of the DNA sequence is then injected into the various potential breeding partners for Lisa, including Tyler Evans. ("Uneasy Lies the Head")