Every cell in your body contains a big book of how to build another you.
Although it's approximately 3 billion letters long only a small fraction of it contains instructions on making humans.
Imagine trying to use a workshop manual but it reads like somebody messed up at the publishers. There are a few paragraphs of meaningful text followed by pages of gibberish, another page or so of useful instructions then 9 more of random words. Some of it looks like copies of original text but full of typing errors. Sometimes there are a few words repeated over and over thousands of times.
Your genome looks like a teenage boys bedroom and that is not unique to humans, it is what most genomes look like. By any possible measure a human is more complex than an onion and yet the species Allium sepa has a genome 5 times as large as ours and wild garlic, Allium ursinum is 10 times as big.
So what's going on? Well a large percentage of the human genome is made up of code that is freeloading. It gets copied along with the code for making proteins and the regulatory code that controls that process, but it contributes nothing to the task of making human bodies.
Geneticists know exactly how most of it ended up in our genome to begin with. Some of it came from accidental duplication, some of it is old broken genes and a lot of it is made up of various types of transposons. These bits of code use a function similar to copy+paste to insert themselves repeatedly into the code.
A small percentage of this code has been domesticated and become functional. In a later post we will see how our colour vision was made possible by accidental gene duplication. Some of it is harmful. We saw in thread number 8 that ALU Elements have been linked to heart disease and cancer among other ailments. Most of it is more like that stuff in the shed that might come in handy one day - usually the day after you throw it out.
The huge amount of non-coding DNA is exactly what evolution would predict. It is a significant challenge to creationism.
If anybody is tempted to say "Encode" please read this hugely informative paper first.
On the immortality of television sets: “function” in the human genome according to the evolution-free gospel of ENCODE. by Dan Graur et al ...
| Part 1 - Protein Functional Redundancy .......... | Part 6 - Human Chromosome 2 |
| Part 2 - DNA Functional Redundancy | Part 7 - Human Egg Yolk Gene |
| Part 3 - ERVs | Part 8 - Jumping Genes |
| Part 4 - Smelly Genes | Part 9 - Less Chewing More Thinking |
| Part 5 - Vitamin C |