Spermatogonia dividing

During embryonic development, the cells destined to become spermatozoa, i.e. the germ cells, divide to form spermatogonia, of which there are many thousands in each testis. Spermatogonia are, in fact, stem cells. Spermatogenesis begins at puberty and continues throughout life. It is divided, arbitrarily, into three parts ... 

Leonard. A. Linden. G. (1972) Observation of dividing spermatocytes for chromosome aberrations induced in mouse spermatogonia by chemical mutagens. Mutat. Res., 16, 297-300 Lide. D.R.. ed. (1997) CRC Handbook of Chemistry and Physics, 78th Ed., Boca Raton, FL, CRC... 

Packer Al, Besmer P Bachvarova RF. 1995. Kit ligand mediates survival of type A spermatogonia and dividing spermatocytes in postnatal mouse testes. Mol. Re prod. Dev. 42 303-10... 

The (male) larval auxocyte stage therefore appears to have some particular attributes of metabolism which allow this mechanism to operate. It might be that the spermatogonia are dividing so rapidly that the mutagenic analogue(s) has no time to be effective, whereas in the auxocyte stage it has. 

FIGURES 1. Dividing spermatogonia, 2. Dividing spermatocyte I, 3. Dividing spermatocyte II with an X chromosome, and 4. Dividing spermatocyte II with a Y chromosome. 

The characteristic meiotic configurations of spermatocyte I chromosomes at the diakinesis first metaphase stage thus provide a reliable technique for the detection of rearrangements or other chromosome aberrations induced in spermatogonia of the treated males spermatocyte test on treated males). Cytological analysis of dividing spermatocytes can also be used to confirm in Fi males the presence of translocations indicated by semisterility, the Fi females being indirectly tested by examination of sons F translocation test) (Table 1). 

---