Human genetics is the study of inherited biological traits passed down from parents to children through genes. Human beings have more than twenty thousand genes, which are sequentially arranged on cellular structures called chromosomes. Every cell in the human body normally contains forty-six chromosomes arranged in twenty-three discrete pairs collectively known as the genome. Within chromosomes are chemical molecules that hold the body's encoded genetic information called deoxyribonucleic acid, or DNA. Cells also carry a related chemical molecule known as ribonucleic acid, or RNA, which is structurally similar to DNA but is single-stranded rather than double-stranded and displays some differences in its chemical composition.
The twenty-three chromosome pairs that comprise the human genome contain a complete set of genetic instructions...Read more