- Basic Characteristics
- Oocyte is an immature female germ cell produced in ovary during gametogenesis
- Contains yolk granules for early development and rich cytoplasm
- Only normal human secondary oocyte has 23,X chromosome
- Forms cell-nest space within ovum
- Maternal Contributions
- Receives mitochondria, nucleolus, and ribosomes from maternal cells
- Stores proteins in cytoplasmic lattices for embryo development
- Provides DNA repair capability during prophase I arrest
- Maintains maternal control of embryonic development
- Paternal Contributions
- Spermatozoon contributes haploid genome and centrosome
- Provides activating factor to activate dormant oocyte
- Some species acquire entire centrosome maternally
- Special Features
- Cumulus-oocyte complex surrounds oocyte in Graafian follicle
- Cumulus expansion critical for oocyte maturation
- Can be cryoconserved for genetic research
- Nondisjunction can lead to aneuploidy in oocytes