Ovogenesis sequence. Animation showing the genetic and cellular changes in the process of ovogenesis (also called oogenesis), the production of an ovum (female gamete). This is the cellular basis of the female part of sexual reproduction, and takes place in the ovaries. The process starts with an oogonium (or ovogonium) at upper left. These are formed by mitosis, remaining diploid (2n) with two sets of chromosomes (red and blue). The following stage is the formation of a primary oocyte (lower centre), which is also diploid. This is followed by the first meiotic division (meiosis), reducing the number of chromosomes and producing a haploid (n) secondary ooctyte (upper centre) with the small daughter cell called a polar body. This is followed by further (secondary) meiotic division, producing two more polar bodies. The three polar bodies, along with their chromosomes, are ultimately discarded, leaving the ootid to mature into an ovum (egg cell, lower right). For this animation with English labels, see K004/2006. | |
Licence : | Droits gérés |
Crédit : | Science Photo Library / Biocosmos / Francis Leroy & Valerie Rouvroy |
Model Release : | Non requis |
Durée : | 29 Secondes |
Aspect ratio : | 16/9 |
Restrictions : | - |