Online ISSN : 1348-7019
Print ISSN : 0011-4545
Chromosome Survey of Some Australian Tettigoniids (Orthoptera-Tettigonioidea): Two Species with Neo-XY Sex-Determining Mechanism
Amilton Ferreira
ジャーナル フリー

1969 年 34 巻 4 号 p. 511-522


The chromosome number of 11 species of Australian tettigoniids, (Orthoptera-Tettigonioidea) are reported in this paper. The main characteristics of the karyotype of these species are given in the following table.
In Polichne parvicauda (specimen no. 6) and Caedicia marginata a centric fusions between the former X and a small autosome was found. These fusions gave rise to a neo-XY sex-determining mechanism in both species. Besides, two centric fusions between autosomes occurred in the former species, forming two pairs of metacentric chromosomes and reducing the chromosome number to 2n=16.
In Torbia viridissima a reduction to 2n=19 due to an integration of chromatin between apparently two small autosomes took place.
The desynchronized movement of the chromosomes during first anaphase due to their bimodality in length as well as the difference in chiasma frequency was discussed.

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