The main role of telomeres in chromosomal DNA is to prevent DNA degradation. Telomeres are repetitive nucleotide sequences located at the ends of chromosomes, and they serve as protective caps. During cell division, the enzymes that replicate DNA cannot fully copy the very end of the chromosome, which leads to a gradual shortening of the DNA with each replication cycle.

Telomeres help to protect the coding regions of the DNA from being lost due to this shortening process. Without telomeres, important genetic information would be degraded, leading to chromosomal instability and cellular aging.

Contrary to some misconceptions:
- Telomeres do not directly facilitate DNA replication but rather protect the ends to ensure replication occurs without loss of crucial data.
- They do not initiate gene transcription, as this is regulated by promoter regions and transcription factors within genes.
- They also do not promote chromosome recombination; instead, they help maintain chromosome integrity by preventing end-to-end fusions.

Therefore, the correct answer is Option 2: Prevent DNA degradation.

Reference: Molecular Biology of the Cell, 6th Edition, Chapter 18: DNA Replication, Telomeres and Telomerase