Cytosine is the "C" of the four bases that make up DNA. Cytosine always pairs with guanine. The other bases are adenine (A), guanine (G), and thymine (T).
Complementary sequences are opposing strands of DNA. They bond together to form the double helix. The bases always complement one another. Adenine and thymine pair together. Cytosine and guanine pair together.
The CODIS system uses marker locations in the autosomal DNA. In the United States, the FBI maintains a CODIS test result database to identify people and solve crimes.
The Cohanim Modal Haplotype (CMH) is the Y-chromosome (paternal) profile most frequently found in men with an oral tradition of Cohen ancestry. It is a Y-chromosome DNA STR (Short Tandem Repeat) haplotype.