Chromosomes in two bug species of Hebrus (Hebridae, Heteroptera). The occurrence of neo-XY sex chromosome system in Heteroptera

: Nokkala S, Nokkala C

Publisher: UNIV FLORENCE BOTANY INST

: 1999

: Caryologia

: CARYOLOGIA

: 52

: 1-2

: 27

: 30

: 4

: 0008-7114

DOI: https://doi.org/10.1080/00087114.1998.10589150

Chromosomes in two species in the genus Hebrus (Hebridae, Heteroptera) mere studied. The species H. ruficeps (Th.) showed the chromosome number 2n = 22A + XY with achiasmate sex chromosomes, which divided in the first meiotic division and separated from one another at the second division. H. pusillus (Fn.) displayed 2n = 22A + neo-XY. The chromosomes of the neo-XY bivalent separated prereductionalIy in the first division. Both species lacked m-chromosomes. It was suggested that although the XY sex chromosome system prevails in Heteroptera, the formation of the neo-XY system has taken place in an XO ancestor after the loss of the Y chromosome.