I am by no means an experienced gardener. I keep a few plants (basil, rosemary, chives) on my widowsill to add some fresh herbs to my meals. My first basil plant flowered and wilted so I harvested the seeds and planted them. I ended up with the plant you see here:

Any idea why the leaves would split like this? Is the plant unhealthy or just a mutation? It seems like every opposite leaf is mutant like this, you can see the leaf coming in on the top right is starting to curl up and a few leaves below are doing the same. I thought this was interesting and I'd like to know what's going on! Lemme know, thanks!