FOOTNOTE. “”Zygotic drive is an unusual form of genetic conflict because it directly reduces Darwinian fitness by killing or debilitating offspring. It is favored by gene-level selection when there is competition among siblings for limiting resources. By killing or weakening noncarrier competitor siblings, the gene(s) coding for zygotic drive gain a selective advantage because their survival is increased at the expense of siblings carrying alleles that are not identical by descent—despite any fitness loss to the parents, siblings, or other parts of the genome.”
http://cshperspectives.cshlp.org/content/7/3/a017608.full