Final answer:
The absence of DNA ligase in a cell would lead to the accumulation of unrepaired Okazaki fragments during DNA replication, which can cause mutations or cell death.
Step-by-step explanation:
If DNA ligase were missing in a cell line, the expected abnormality would be the accumulation of unrepaired Okazaki fragments on the lagging strand during DNA replication. DNA ligase is crucial for sealing nicks between adjacent Okazaki fragments, thereby creating a continuous DNA strand. Without DNA ligase, cells would have significant problems with DNA replication, potentially leading to mutations or cell death.