Final answer:
Ligase-deficient strains of E. coli do exhibit altered DNA replication due to the inability to join Okazaki fragments effectively, leading to the accumulation of fragmented DNA and disrupted chromosomal replication.
Step-by-step explanation:
DNA ligase is an essential enzyme in chromosomal replication, particularly for joining Okazaki fragments on the lagging strand during DNA replication in E. coli. In ligase-deficient strains of E. coli, DNA replication is indeed altered. Without the proper function of DNA ligase, Okazaki fragments cannot be efficiently joined, leading to the accumulation of short DNA fragments rather than the formation of a continuous DNA strand.
Research conducted by Reiji Okazaki revealed that in T4 phage with deficient DNA ligase, E. coli host cells showed an accumulation of unjoined DNA fragments. This confirms the importance of the ligase in the replication process and particularly its role in sealing the nicks between Okazaki fragments, which are synthesized discontinuously against the lagging template strand during replication.
Therefore, the direct answer to whether ligase-deficient strains of E. coli have altered DNA and chromosomal replication is true.