There are literally thousands or more genes in our DNA that don't work.
We share 22 unique endogenous retroviral genes with the chimpanzees. One, very peculiar one has to do with c-vitamin synthesis. Humans (and chimps) have to eat fruit to get C. All other animals (except 3 other species for other genetic reasons) have to consume things with C vitamin to get it. Our gene is malfunctioning because of the ERV. And we have the exact same modification ("mis-spelling" of gene) that the chimps have. The only way to get that is to share mom and dad at some point. We both come from a common donor that had this malfunction. How is that for a design that accomplish it's purpose?
Boy, that is a giant leap to an unwarranted conclusion. The so-called "junk" DNA code has been shown to have functions necessary for life. The same Creator who made the chimp, the mouse (with whom we also share similar DNA), and the banana (yep, we share half the banana's DNA), created mankind as well. It should not seem strange if the same materials and algorithms were used by the master Designer.
Interesting to me, the Bible reveals we are far from what God created us to be. "Sin entered into the world, and death through sin, and so death spread to all men." (Romans 5:12) I believe the harm done by man's rebellion created defects of all sorts within us. So I am not surprised if genes are defective in us. Animals, on the other hand, were not created to live forever. (2 Peter 2:12)