Every day they checked which parts of the chromosome had been switched off. (sciencedaily.com)
Because the members of a breed have similar stretches of DNA, we can use our 200,000 + genetic markers to determine what part of each chromosome in your dog came from what breed. (my.embarkvet.com)
This was the crucial insight which indicated that those units, genes, were indeed parts of chromosomes. (newscientist.com)