WHY SO MANY BITS AND BYTES? To understand, try tackling this recipe. There's a lot more to this, but I've condensed for easier-digestion.
- lots of money
- polar bear
- next-generation sequencing (DNA-translating) technology
- the best goddamned computer ever known to man
1. Collect high-quality samples from a polar bear without getting eaten. Isolate DNA.
2. Load DNA into a next-generation sequencer to generate fragments, or "reads" of genetic code that correspond to your DNA. The genome (all DNA) is a LONG code made up of billions of 4 unique units/"letters"/or bases ( A, T, G, and C). DNA also has 2 (very long) strands: T on one strand will always pair with A on the other, and G always with C. Since DNA is so long, the sequencer chops the DNA up into tiny segments and, by "reading" individual strands, builds complementary units to replicate the fragments. Each of the 4 units, during replication, emits a unique signal that can then be detected to determine which base (or sequences) make up the fragments.
3. Align/assemble the overlapping "reads" until you have the whole genome in sequence.
4. Align the genome to other genomes that have already been sequenced, especially familiar (e.g., human) ones, where we know what codes for what (what combination of A, T, G, C translates into what trait/ behaviour).
These guys recently perfected this recipe. Using 79 polar bears and 10 brown bears, they found that, after a recent split of brown bear lineages (large populations of individuals/genomes that changed so much over time they became more and more different), one gave rise to the polar bear (genome). Regions of the polar bear genome that were targets of positive selection (most important for survival and thus persist in the genome today) correspond to genes that regulate heart disease, break-down/storage of fat and color pigmentation (in humans).
Given the Kentucky Fried polar bear diet--they gorge on seal fat and whale blubber to keep their bellies full for long periods of time--it's no surprise that they've found a loophole to eat themselves to the other side without heart break. As for genes coding for color...well how stealthy could a beastly arctic predator be now if he was still brown in a world of white?