Heritable chromosome assays

The same chromosome aberration assay described above can be used to detect numerical chromosome changes (i.e., aneuploidy) in bone marrow cells. Chemicals that cause chromosome damage in germ cells can be detected using in vivo assays, either the dominant lethal assay, a test for structural chromosome aberrations in spermatogonia, or a more preferred test, the mouse heritable translocation assay. 

Another method of monitoring heritable chromosomal abnormalities is the mouse sex chromosome-loss test. This assay differs from the dominant lethal test and heritable translocation test in that it is thought primarily to measure nondisjunctions. In this assay progeny of treated male and female mice are examined for sex-linked phenotypic differences. 

Of the 19 pesticides grouped in Table II, all were negative in five Phase I bioassays and the Phase 2 bioassays performed. These compounds included insecticides (I), fungicides (F), and herbicides (H). Malath ion, parathion, pentachloronitrobenzene (PCNB), and phorate were also negative for heritable chromosomal effects in the mouse dominant lethal test. The six compounds grouped in Table III that were positive in three or more bioassays were acephate, captan, demeton, folpet, monocrotophos, and trichlorfon. Positive results were seen for demeton in all in vitro tests in Phase 1 and Phase 2. Folpet and captan were positive in all Phase 1 and all Phase 2 in vitro assays except the test for unscheduled DNA synthesis in WI-38 cells. Trichlorfon was positive in all Phase 1 and Phase 2 in vitro tests, with the exclusion of relative toxicity tests with E coli and subtiI is. 

Mouse heritable translocation assay Mouse heritable chromosome Heritable chromosome aberrations B25/TG485... 

Assays for chromosomal aberrations In vitro cytogenetic In vivo cytogenetic Micronucleus Dominant lethal Heritable translocation Mammalian germ cell cytogenetic... 

The heritable translocation test, although similar in some respects to the dominant lethal test, differs in that the offspring of the treated males are allowed to reach maturity and are thus available for C3ftologic determination of the type of chromosomal aberration inherited. In this assay treated males are mated weekly to different females over an 8 week period as is done in the domi-... 

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