In case there is still confusion, chromosomes contain both DNA and RNA, along with proteins, though RNA is found only in "small amounts" (Advanced Biology, Kent, OUP). The first line of the wiki article on chromosomes says the same, however, a more authoritative source is the book quoted above, namely Advanced Biology by Michael Kent. The exact page referred to can be seen on Google Books with the search string: "small amounts of rna in chromosomes" "advanced biology" "michael kent".