Ellen Ripley clone

The Ellen Ripley clone is a fictional character portrayed by actress Sigourney Weaver in the movie Alien: Resurrection which is the fourth installement in the Alien series. Although the character is referred to in the movie as "Ellen Ripley" and is portrayed by the same actress, canonically she is only a copy of the original Ellen Ripley, and does not have the same personality or history.

Background
This Ellen Ripley clone is the eighth in a line of clones that have been made from samples recovered from Fury 161, the site of the original Ellen Ripley's death. The recovered samples contained the DNA of Ellen Ripley along with the xenomorph chest-burster that had been incubating in her chest at the time. The original goal of the coling project was to recover the xenomorph only; the cloned host was regarded as a by-product.

After the xenomorph was recovered successfully from the clone host, Dr. Jonathan Gediman, one of the scientists on the project, asked permission to keep her alive so to she could be studied. Dr. Mason Wren agreed, though the main focus of the project would still remain on the xenomorph.

Genetic Fusion
As a result of the genetic experiment, the Ellen Ripley clone is a genetic mix of the original Ellen Ripley's DNA and the DNA of the xenomorph she'd been hosting. It is revealed that the xenomorphs have a genetic memory, and because of this in the clone having vague memories belonging to both the original Ellen Ripley and the xenomorph. This results in the clone initially not knowing whether to be loyal to humans or the aliens.

Additionally, the clone has physical "bonuses" as a result of the genetic crossing, including superhuman strength, acid for blood (which is much milder than the pure xenomorph blood), heightened senses and an apparent mental connection with the xenomorph hive.