Bridge to the New World How and when humans first came to the Americas has long been a topic of intense debate. Theories to explain the colonization of the New Worldâthe last great habitable landmass to be occupied by humansâfocus on the Bering land bridge, or Beringia, which emerged between Siberia and Alaska during the last ice age.
DNA ligase I: ligates the nascent DNA of the lagging strand after the Ribonuclease H has removed the RNA primer from the Okazaki fragments. DNA ligase III: complexes with DNA repair protein XRCC1 to aid in sealing DNA during the process of nucleotide excision repair and recombinant fragments.
When DNA is being replicated, it forms a replication fork that was created during the helicase process that separates the DNA strand. The strands that are separated are called the leading strand and the lagging strand accordingly. The leading strand is synthesized in the 5'-3' direction.