Online ISSN : 1348-7019
Print ISSN : 0011-4545
Chromosome Number and Sex-determining Mechanism in the Dragonfly Hemianax ephippiger (Burmeister)
B. R. SeshacharShanta Bagga
ジャーナル フリー

1962 年 27 巻 4 号 p. 443-449


The chromosome number of Hemianax ephippiger (Burmeister) has been recorded for the first time. The diploid chromosome number in both males and females is 14. The sex-determing mechanism is of XX:XY type. The X-chromosome is the largest of all and in the spermatogonial metaphase plate, it is markedly bent. The Y-chromosome is medium sized and rodshaped. Metrical study of fifteen metaphase I plates reveals two very long, ten medium and two very short chromosomes. The m-chromosomes are the smallest of all. The X- and Y-chromosomes both possess euchromatic regions which form pairing segments at meiosis. Anaphase I results in two types of daughter nuclei, one with X- and the other with Y-chromosome. Anaphase II is equational for the sex and all other chromosomes.

© The Japan Mendel Society