What characterizes the 3' overhang of telomeric sequences?

The 3' overhang of telomeric sequences is characterized by repeated stretches of nucleotide sequences that consist primarily of adenine (A) and thymine (T) followed by several guanine (G) bases. This specific arrangement allows for the formation of a protective structure at the ends of chromosomes, known as the telomere. The repeated nature of these sequences plays a critical role in safeguarding chromosomal integrity during DNA replication by preventing degradation or fusion with other chromosomes.

Telomeres serve to maintain the stability of chromosomes by ensuring that the genetic information in the chromosome is not lost with each replication cycle. The inclusion of guanine-rich sequences helps form a looped structure, effectively shielding the ends of the chromosome from being recognized as broken DNA, which could trigger repair pathways that may lead to chromosomal rearrangements. Thus, the correct characterization of the 3' overhang is that it contains repeats of A's or T's along with several G's.