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4TH ANNUAI.MEETING. HEIDELBERG

15 ADLER, I.-D., Abteilung ftir Genetik, Gesellschaft ffir Strahlen- und Umweltforschung, D-8o42 Neuherberg (W. Germany)

Primordial germ cell sensitivity to mutagenic effects of T E M Trietllylenemelainine (TEM) is known t o induce specific locus nmtations and translocations in mouse spermatogonia (CATTANACH, Mutation Res., 3 (r066) 346; CATTANACHAND WILLIAMS, Mutation Res., 13 (Iq7 I) 37 I, as well as dominant lethal mutations in nlature oocvtes (CATTANACH,lilt. J. Radial. Biol.. 3 (IQ5()) 288; (;EN[-ROSO el al., Mutation Res., I I (1971) 4tI. Therefore TEM was used to stud) the effect of a chemical mutagen on comparable germ cell stages in both sexes .primordial ,~.gonia and spernlatogonia--with the dominant lethal assay. An additional comparison of the TEM effect on primordial spermatogonia and adult spermatogonia was carried out by analyzing primary spermatocytes for the occurrence of recipr~mal translocation.~. IO- and I I - d a y old embryos were treated in utero with () different doses of TEM ranging from o.o5 to o.5 mg/kg. These animals were out-crossed for the dominant lethal assay at the age of IO-r2 weeks. No dominant lethal mutations were found fl,r either sex, but a pronounced cell killing effect was .bserved for b~,th primordial oogonia and spermatogonia. From IO males per dose treated in uh'ro 5oo-.Iooo primary spermatocytes per dose were analyzed. From IO nlales per dose treated as adults 5oo primary spermatocytes per dose were analyzed I2O days after treatment. In all, 5 translocation multivalents were observed among 470o diakinese.--metaphases I in the pre-natally treated experimental groups versus mine in 5oo cellb of the concurrent controls. This result is due to change (P -- o.6). In treated adult males a total of 11 translocation multivalents were found among 300 diakineses metaphases [ of ttle experilnental groups versus none in lOOO cells of the c