Each chromosome contains many genes that direct the production of proteins needed by cells.

VOA: special.2010.03.23

But some people are born with an extra copy of the twenty-first chromosome.

VOA: special.2009.09.09

Miscarriages are usually caused by chromosome problems that prevent the baby from developing.

VOA: special.2010.08.11

A chromosome contains molecules of deoxyribonucleic acid, better known as DNA.

VOA: special.2009.12.08

"When Darwin first proposed his theory in eighteen fifty-nine, he had no concept of a gene, no concept of a chromosome, no concept of mutation, and certainly no concept of things like DNA and RNA."

VOA: special.2009.12.01

"We are here today to announce the first synthetic cell -- a cell made by starting with the digital code in the computer, building the chromosome from four bottles of chemicals, assembling that chromosome in yeast, transplanting it into a recipient bacterial cell and transforming that cell into a new bacterial species."

VOA: special.2010.07.20