Down syndrome is a genetic disorder caused by an extra chromosome 21, affecting brain and body development. It leads to ...

It is a genetic condition caused when an unusual cell division result in an extra full or even partial copy of chromosome 21.

Each human body cell contains 46 chromosomes. These can be arranged into 23 pairs. Each chromosome in a pair carries the same types of genes. The 23rd pair are the sex chromosomes: In females ...

Others cells in your body contain 46 chromosomes: 23 from your father and 23 from your mother. Your egg (or sperm) cells contain only half that number—a total of 23 chromosomes. When an egg and ...

Each human body cell contains 46 chromosomes. These can be arranged into 23 pairs. Each chromosome in a pair carries the same types of genes. Cells grow then divide by mitosis only when we need ...

Tjio and Levan Use Improved Methods to Establish the Chromosome Number as 46 In the decades following Painter's work, scientists continued to refine their methods for preparing chromosomes for ...