Cytological studies on the mosaic silkworms induced by low temperature treatment

Mosaic silkworms were induced when the hybrid eggs of two strains with different egg color and larval markings were exposed to low temperature. Cytological studies were conducted to find out the relation between mosaic larval pattern and ploidy in reproductive cells along with demonstration of chromosomes in the mosaic embryos. — Mosaic eggs eith the characters of both the father and the hybrid were two types, one with large serosa nuclei (LN-mosaic) and the other with small serosa nuclei (SN-mosaic). The cytological studies demonstrated that LN-mosaic individuals were 2n/4n, while SN-mosaic ones were n/2n. In both types of silkworms, cell ploidy level in nuclei of synkaryon origin was two times that of androgenic ones. — From the results obtained in the present studies as well as in the previous studies, a possible mechanism of induction of mosaicism in silkworms by cold shock is contemplated.