Human female meiosis revised: new insights into the mechanisms of chromosome segregation and aneuploidies from advanced genomics and time-lapse imaging

ABSTRACTBACKGROUNDThe unbalanced transmission of chromosomes in human gametes and early preimplantation embryos causes aneuploidy, which is a major cause of infertility and pregnancy failure. A baseline of 20% of human oocytes are estimated to be aneuploid and this increases exponentially from 30 to 35 years, reaching on average 80% by 42 years. As a result, reproductive senescence in human females is predominantly determined by the accelerated decline in genetic quality of oocytes from 30 years of age.OBJECTIVE AND RATIONALEUnderstanding mechanisms of chromosome segregation and aneuploidies in the female germline is a crucial step towards the development of new diagnostic approaches and, possibly, for the development of therapeutic targets and molecules. Here, we have reviewed emerging mechanisms that may drive human aneuploidy, in particular the maternal age effect.SEARCH METHODSWe conducted a systematic search in PubMed Central of the primary literature from 1990 through 2016 following the PRISMA guidelines, using MeSH terms related to human aneuploidy. For model organism research, we conducted a literature review based on references in human oocytes manuscripts and general reviews related to chromosome segregation in meiosis and mitosis.OUTCOMESAdvances in genomic and imaging technologies are allowing unprecedented insight into chromosome segregation in human oocytes. This includes the identification of a novel chromosome segregation error, termed reverse segregation, as ...
Source: Human Reproduction Update - Category: OBGYN Source Type: research