Mammalian male germ cell cytogenetics.
The methods used for the detection of chemically induced chromosome damage in male germ cells are discussed. These tests have been divided into direct and indirect cytogenetic methods. The direct methods assess chromosome damage in the dosed animal but analysis is restricted to the dividing spermatogonia and spermatocytes. Using indirect methods, chromosome damage is assessed in the F1 progeny of the dosed male and analysis covers all germ cell stages. Both methods can provide evidence of germ cell exposure but the data obtained from the indirect tests are considered more relevant since a positive result clearly constitutes unequivocal evidence of transmitted damage. The analysis of one-cell embryos from matings involving dosed parents is considered to be the most useful indirect test system since both structural and numerical aberrations in male and female F1 offspring can be assessed. Although relevant to the assessment of mutagenic hazard, the technically demanding methods used in the germ cell techniques prevent their use for preliminary screening programmes.
Albanese
R
R
ICI Pharmaceuticals Division, Macclesfield, Cheshire, UK.
D000818:Animals; D002869:Chromosome Aberrations; D002970:Cleavage Stage, Ovum / Q000648:ultrastructure; D003582:Cytogenetics; D005799:Genes, Dominant / Q000187:drug effects; D005804:Genes, Lethal / Q000187:drug effects; D008297:Male; D009152:Mutagenicity Tests / Q000379:methods*; D013090:Spermatocytes / Q000187:drug effects; D013093:Spermatogonia / Q000187:drug effects; D013094:Spermatozoa / Q000187:drug effects* / Q000648:ultrastructure; D013997:Time Factors; D014178:Translocation, Genetic / Q000187:drug effects