GENETIC CHEATING. “A striking feature of meiosis is its apparent fairness: under Mendel’s first law of inheritance, each allele has a 50% chance of ending up in any given gamete. However, there are many selfish genetic elements that increase their chances above 50% by subverting the mechanism of meiosis.”
http://biorxiv.org/content/biorxiv/early/2016/04/28/050831.full.pdf