Final answer:
The absence of Mg2+ can hinder or fail the DNA replication process in vitro as Mg2+ ions are essential for stabilizing the DNA structure and enabling DNA polymerase to function properly.
Step-by-step explanation:
When the researcher attempts to replicate DNA in vitro but leaves out the Mg2+ component, he can expect the replication process to be hindered or even fail.
Mg2+ ions are essential for the function of DNA polymerase, the enzyme responsible for synthesizing new strands of DNA during replication. Mg2+ ions help to stabilize the structure of DNA and enable the DNA polymerase to properly bind to the template strand and incorporate nucleotides.
Without Mg2+, the DNA replication process may not proceed efficiently or accurately, leading to incomplete or faulty replication.