In case of eukaryotes replication initiates at

In eukaryotes, replication initiates at specific sites on the DNA called replication origins. These replication origins are marked by specific DNA sequences that are recognized by proteins involved in the initiation of DNA replication. The initiation of DNA replication is a highly regulated process that involves the assembly of a pre-replicative complex (pre-RC) at replication origins.

The pre-RC consists of several proteins, including the Origin Recognition Complex (ORC), Cdc6, Cdt1, and the Minichromosome Maintenance (MCM) complex. These proteins are recruited to replication origins during the G1 phase of the cell cycle. Once assembled, the pre-RC serves as the starting point for the initiation of DNA replication.

During the S phase of the cell cycle, which is when DNA synthesis occurs, the pre-RC is activated, and the MCM helicase complex is loaded onto the DNA. The MCM complex acts as a DNA helicase, unwinding the DNA double helix and creating replication forks where DNA synthesis can begin.

Replication origins are distributed throughout the genome and are often associated with regions of open chromatin and regulatory elements. Eukaryotic cells have multiple replication origins to ensure that the entire genome is replicated efficiently and accurately during each cell division cycle.

Overall, replication initiates at specific replication origins in eukaryotic cells, where the pre-RC is assembled and activated, leading to the initiation of DNA synthesis and the replication of the genome.