Ask a Geneticist

We have 46 different chromosomes instead of one big long chain of genes because of many reasons. The first one is because it is easier to reproduce that way. Simple organisms like bacteria only have one chromosome. They only reproduce by duplicated themselves, so variety doesn't matter. With humans and other complex organisms, we reproduce sexually meaning we get chromosomes from both parents. With different chromosomes, more different groupings are possible (10 trillion) and the process is completely random. Genetic diversity is important since we have to be different to survive. If a disease started to cause havoc, many would die. The ones who live would have different genes, and that is what will help us to continue the human race.

Our genes are in certain chromosomes for no specific reason. Over time (generations), genes move around and group themselves in different chromosomes. Genes that are associated with each other can be separated by a few chromosomes. However, some parts are organised. A process called gene duplication helps genes become more organised. Basically, duplicated genes develop new jobs over time, and genes close to each other generally do similar jobs. Scientists still aren't completely sure about the final answer to many of our questions about genetics (and other mysteries of our world), but discoveries are being made by the minute, and it's only a matter of time.