Ask A Geneticist

By reading these websites, I learned many facts about chromosomes and DNA. A chromosome is a package containing a chunk of a genome, which is an organism's genes. A chromosome is similar to a package which helps a cell to keep a large amount of genetic information neat, organized, and compact. Chromosomes are made of DNA and proteins. Some simple organisms, such as bacteria, can package their their entire genome (the genetic information) in a single chromosome. However, for more intricate organisms, such as humans, the genome is much larger, and more chromosomes are required to store all of the genetic information. The amount of chromosomes that an organism has depends on the species, and is therefore not a fixed amount. Closely related species usually to have a similar number of chromosomes. For instance, chimpanzees, our closest cousins, have 48 chromosomes in each of their cells, while we have 46 chromosomes. It is expected for more complex organisms to have more chromosomes, but nature doesn't work that way. Surprisingly, goldfish, who are fairly simple organisms, have 96 chromosomes, in comparison to humans, who have 46 chromosomes. The number of chromosomes that an organism has is unique to its species, and it is not very specific.