4.4. Is Christina related to the porn star Colleen Applegate?

No. She's not the same person. They're not sisters. The only relation
between them that the entire collective knowledge of alt.tv.mwc and
alt.fan.christina-applegate has ever discovered is that their names
sound alike.

Applegate is an uncommon surname but hardly unique, for instance,
columnist Liz Applegate.

Christina has no full siblings. She has a half-sister and half-brother,
both of whom are emphatically not dead porn stars.