Notes on the chromosomes of two species of cockroaches

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  • ワモンゴキブリとチャバネゴキブリの染色体

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Chromosomes of two species of cockroaches, Periplaneta americana. L. and Blattella germanica L. which were derived from the colony having been maintained in the Agricultural Chemicals Research Laboratories, Sankyo Co., Ltd., Tokyo, were studied in male germ cells. The American cockroach, Periplaneta americana, was found to possess 33 diploid chromosomes in the spermatogonia (Figs. 1 and 2), and 17 haploid chromosomes in the primary spermatocytes (Figs. 3 and 4). The occurrence of an unpaired X-chromosome was noted. As a result of the first meiotic division, two kinds of the secondary spermatocytes, 17 and 16 in n number, were produced (Figs. 6 and 7). The former is the X-class cell and the latter the non-X-class one. In the German cockroach, Blattella germanica, the spermatogonial chromosomes were 23 in number (Figs. 10 and 11). Twelve bivalents including an unpaired X were observed at metaphase-I (Figs. 12 and 14). Two kinds of the secondary spermatocytes were observed : one was the X-class cell, 12 in n number (Fig. 15), while the other showed 11 chromosomes without X-element (Fig. 16). In both species, the X-chromosome showed a precocious migration to one of poles in the first division (Figs. 5 and 13). The secondary spermatocytes of polyploid nature were found occur in Periplaneta americana (Figs. 8 and 9).

Journal

  • 昆蟲

    昆蟲 35 (4), 337-342, 1967-11-30

    東京昆蟲學會

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