Before the completion of the human genome project, many scientists were expecting to find 100,000 or more genes in our genome. This was based on the assumption that because we are one of the most complex creatures on Earth we should have lots of genes. However, it turned out we only have around 24,000 genes.
While bees and wasps inject venom when they sting, mosquitoes simply bite to feed on your blood. The bumps and itchiness that follow come from an anticoagulant that the mosquito injects to prevent your blood from clotting, which triggers a mild allergic reaction that includes the typical round, red bumps.