 mammalian sperm carry not only the paternal genome but also the paternal epigenome in the form of DNA methylation, retained histones, and non-coding inase. These epigenetic marks have been linked to protein-coding genes that are critical for pre-implantation embryonic development, although there is no evidence that they play a role in fertilization and early development. Two manor clusters consisting of five manors, MEHR, 34B, C and MEHR for 49A, B, C, are found in sperm, but absent from ocytes. MEHR, 34C has been shown to be necessary for the first cleavage division in vitro, while MEHR for 49A, B, C are essential for normal fertility. Entrocytoplasmic injection of either MEHR, 34B, C or MEHR for 49, null sperm leads to normal fertilization, normal pre-implantation development, and normal birth rates. However, MEHR, 34B, C and MEHR for 49 double knockout, MIRDKO. This article was authored by Xueqiao Yuan, Zhongtang, Ying Zhong, and others. We are article.tv, links in the description below.