Satellite DNA is concentrated at centromeres and ends of chromosomes.

• A. Centromeres
• B. Telomeres
• C. Centromeres and Telomeres
• D. Satellite DNA

Answer: (D)

Satellite DNA refers to highly repetitive, noncoding DNA arranged in tandem repeats that form large blocks in heterochromatin. In many organisms these blocks are located around centromeres (pericentromeric regions) and, in some cases, near chromosome ends (subtelomeric regions). Because of this typical distribution, saying that satellite DNA is concentrated at centromeres and ends captures how these repetitive sequences are organized in the chromosome, which is why this is the best description. Centromeres themselves are defined by kinetochores and specific chromatin, and telomeres are defined by their own telomeric repeats; while satellite DNA can be present near telomeres, the concept that best fits the statement is the category of satellite DNA itself.