Hirotami T. Imai

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A quantitative analysis of the alterations of constitutive heterochromatin in eukaryotic chromosomal evolution was attempted using the accumulated C-banding data available for mammals, amphibians, fish, ants, grasshoppers, and plants. It was found that these eukaryotes could be classified into two types by their C-banding patterns: 1) Type I included(More)
Aspects of chromosomal mutation and karyotype evolution in ants are discussed with reference to recently accumulated karyological data, and to detailed karyotype analyses of several species or species complexes with low chromosome number and unusual chromosomal mutations (the complexes of Myrmecia pilosula (Smith) (n = 1, 5 or 9 to 16); M. piliventris Smith(More)
The life cycle of the myrmicine antPristomyrmex pungens was investigated. Colonies of this species are usually composed of several thousand small workers, although a few males (2–3 %) occasionally appear during June and July in mature colonies, and large workers with ocelli and abortive spermathecae (here termedergatoid queens) were observed extremely(More)
The mammalian amelogenin (AMEL) genes are found on both the X and Y chromosomes (gametologous). Comparison of the genomic AMEL sequences in five primates and three other mammals reveals that the 5' portion of the gametologous AMEL loci began to differentiate in the common ancestor of extant mammals, whereas the 3' portion differentiated independently within(More)
Chromosomes from several species of ants from the genus Myrmecia were hybridized with deoxyoligomer probes of either (T2AG2)7, the putative insect telomere repeat sequence, or (T2AG3)7, the vertebrate telomere repeat sequence. While both sequence hibridized over a range of stringency conditions, (T2AG2)n was clearly the predominant sequence at the termini(More)
105 Australian ant species, including members of the important primitive genera Amblyopone and Myrmecia, were karyotyped using a C-banding air-drying technique. The observed haploid numbers in this survey ranged from 2n=84 (the highest known in the Hymenoptera) to 2n=9. Seven types of chromosome rearrangement were detected, namely: Robertsonian(More)
The chromosomal localization of 28S rDNA was investigated in 16 species of the Australian ant genusMyrmecia, with 2n numbers ranging from 4 to 76, using the fluorescence in situ hybridization method and karyographic analysis. A unique phenomenon was observed: the number of chromosomes carrying 28S rDNA increases from 2 in species with low chromosome numbers(More)
The diploid chromosome number in the female formicine ant, Lasius sakagamii, is 30, while the haploid number in normal males is 15. Six of the 30 studied colonies (20%), however, contained many diploid males. Although the body size of the diploid males was, on average, larger than that of the haploid males, both types of males showed normal external and(More)
The nature of the centromere and the orientation in meiosis of silkworm chromosomes were investigated using the trivalent of the F1 hybrid between the wild and domestic silkworm and X-ray-induced aberrant chromosomes as well as normal silkworm chromosomes. The results of the experiments were as follows: (1) Pro-metaphase chromosomes showed no distinct(More)