The 23rd chromosome base pair contains what are known as our sex chromosomes. For most females, this pair contains two X chromosomes, while for most males, it contains one X chromosome and one Y ...

Many animals use a special pair of chromosomes to determine their sex during development, but how did this system evolve? Where did these chromosomes come from and how do they change over time?

Why do humans rely on XY chromosomes to determine sex, while birds use ZW—and many reptiles use neither, letting temperature decide instead? Sex determination is remarkably diverse across the animal ...

The body cells of humans and animals contain a double set of chromosomes. One half of the genetic material comes from the mother, the other stems from the father. During the formation of sperm or egg ...