ABSTRACT
Prophase I is the most complicated part of meiosis. For the sake of study, it is subdivided into five substages, the details of which are beyond the scope of this book. Let it suffice to say that it is during the diplotene stage of prophase I that the primary oocyte becomes arrested during its progress through meiosis I (as previously discussed). However, it is during this stage that the oocyte is very active metabolically and synthesizes a variety of important biochemicals. Part of this synthetic activity is obvious in the growth of the size of the oocyte. At a more subtle level, this synthetic activity is stockpiling substances (such as maternal ribosomes and maternal messenger RNA [mRNA] molecules), which will be used to support development before the conceptus' own genes are able to produce ribosomes and mRNA.
