عثمان عبدالله ابراهيم الدوخى

1-Developmental Biology.

2- Cells Differentiation.

3- Ultrastructure of Gametogenesis. 

When the organism reaches maturity, germ cells acquire the ability to differentiate into functional gametes and undergo meiosis to reduce the chromosome number from 2n to 1n. Gametes are produced through the process of gametogenesis.  Spermiogenesis is the process in which spermatids transferred into spermatozoa. Spermatids are spherical cells with centrally located nuclei.

The major events in nuclear modification are: chromatin condensation and morphological changes.
Chromatin condensation helps to streamline the cell by reducing volume. It also may serve a protective function, reducing the susceptibility of the DNA to mutation or physical damage.

Condensation is facilitated by formation of specific DNA-protein complexes. Proteins that may be involved include protamines (small, highly basic, arginine-rich proteins), histone-like proteins or other sperm-specific proteins.

A central question in both developmental and cell biology concerns how the developmental program directs cellular differentiation. Once cell type and pattern decisions have been made, the developmental program remodels fundamental cellular functions like the cell cycle, the cytoskeleton, and the general transcription machinery to give rise to specialized cell types. We investigate the ultrasructure of reptiles spermatogenesis in certain Saudian species. Our current work focuses on the  spermatid differentiation (spermiogenesis). We have discovered that  there are some distinct ultrastructural differences among species.

 Our current work indicates that little was done to investigate oogenesis of Saudian reptiles species. Therefore a second focus of our work  is to build a good  knowledge of ultrastructural details of oogenesis of Arabian reptiles.