Chromosome Behavior in the Spermatogenesis of Oxya yezoensis (an Orthopteran)
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概要
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1. The chromosome behavior in the spermatogenesis of Oxya yezoensis Shiraki (an orthopteran) was studied, in the fall of 1929, as a partial fulfilment to my genetic-cytological studies on the species-for-mation in the genus Oxya, together with those studies on that of O. japonica and O. velox reported in previous paper. 2. Oxya yezoenszs is found only in Hokkaido, where no other species of Oxya is found. The material for the present studies was collected, in early September of 1929, in rice fields in the suburbs of the city of Sapporo. 3. The diploid number of chromosomes found in the spermatogonial division is twenty-three, of which one is the heterochromosome. The number of chromosomes is found to be the same as that of O. velox and O. japonica. 4. The spindle-fibre attachment to the chromosomes in the spermatogonial divisions is consistently telomitic and at their proximal or inner end. 5. The number of multiplication divisions of the secondary spermatogonia is eight, and is found to be the same as in other species. 6. The size of the nucleus at the pre-cryptosome stage of the spermatocytes is about 20.6μ and found to be the smallest in comparison with that of the other species, that is ; in Oxya japonica it is about 22.9μ and in O. velox it is about 24.1μ. 7. The haploid number of chromosomes found in the metaphase of the heterotypic division of the spermatocytes is twelve, being composed of eleven autosomal tetrads and one heterochromosome dyad. 8. The kinds and modes of tetrad-formation in this species have been carefully studied in the pachytene stage, diakinesis, metaphase and anaphase stages of meiosis, and classified into five groups shown in the tables. These were compared with those of O. velox and O. japonica, with the intention of finding any specific differences between the species studied. 9. The spindle-fibre attachment to the eleven tetrads and one dyad in the heterotypic division of meiosis is all telomitic. 10. The heterochromosome shows heteropycnosis during the spermatogonia and spermatocytes, and its behavior in the pre-heterokinesis is precessive, these features being the same as in the cases of O. velox and O. japonica. 11. The haploid number of chromosomes found in the homeotypic division of the secondary spermatocytes is eleven in one of the daughter cells and twelve in the other, which contains the heterochromosome. 12. The spindle-fibre attachment is telomitic and at the proximal end in all the chromosomes of the secondary spermatocytes.
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関連論文
- Chromosome Behavior in the Spermatogenesis of Oxya yezoensis (an Orthopteran)
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