Human biological sex is determined by the sex chromosomes X and Y. In most cases ... said the chromosome's evolution of palindromes — DNA sequences that read the same forward as backward ...

Sunburns and aging skin are obvious effects of exposure to harmful UV rays, tobacco smoke and other carcinogens. But the effects aren't just skin deep. Inside the body, DNA is literally being torn ...

The Y chromosome is the keeper of family history ... a genealogical puzzle using your power of reasoning and understanding of DNA. When you start the game, you'll find an incomplete family tree ...