Question

Why is it not possible for an alien DNA to become part of a chromosome anywhere along its length and replicate normally?

Answer 1

It is not possible for an alien DNA to become part of a chromosome anywhere along its length and replicate normally because the replication process begins at a particular spot called the origin of replication. Also, replication in eukaryotes occurs in the nucleus during the S phase of the cell cycle when the chromosomes are in their extended form.