The answer is: BIT, BAT, BAN, FAN, FUN.
If you're hooked on sudoku, you should try the letter game called genetic code. Here's an easy example: Put the following words in a sequence so that each one differs from the previous word by just one letter.
FAN | BIT | BAT | BAN | FUN
Now imagine working with words that contain thousands of letters. And, instead of shuffling around recognizable words, you have long, seemingly random strings of As, Ts, Gs and Cs—the letters of the DNA code.
That's what scientists face when they try to track and analyze changes within an organism's genetic material, or genome. The task may sound tough, but it's easy with the help of computers.
Scientists typically start with a collection of gene sequences from different people or organisms. These sequences could come from blood, bodily tissues or even ancient bones.
To figure out when the variations occurred, researchers use computational tools to put the gene sequences in chronological order. In this way, computers are revealing the genetic changes, combinations and quirks that create the Earth's remarkable biological diversity.