Karyotypes of Some Lepidoptera Chromosomes and Changes in Their Holokinetic Organisation as Revealed by New Cytological Techniques

Abstract

A new air drying technique combined with ASG banding has enabled the construction of detailed karyotypes for two species of butterfly, Pieris brassicae L. and Polyommatus icarus Rott. Primary constrictions (primary centromeres) at early mitotic metaphase are clearly visible on chromosomes before they become highly condensed, suggesting that the chromosomes are not holokinetic for the entire cell cycle. Primary centromeres were not seen at meiosis. Confirmation that the female is the heterogametic sex was obtained, and size comparison and banding patterns indicate that the sex chromatin body in the female interphase cells is a heteropycnotic X chromosome. The sex chromosome pair in these species is heteromorphic. In a third species Pieris napi L. which also has heteromorphic sex chromosomes in the female, achiasmatic bivalents were seen in oocyte meioses. Chiasmata were found, however, in the male meiotic cells of all three species. © 1975, Japan Mendel Society, International Society of Cytology. All rights reserved.