Unequal sex chromosomes in a moth, Lozotaenia forsterana F. (Lepidoptera: Tortricidae)

Abstract

The chromosomes of the biggest bivalent in the female of the tortricid moth Lozotaenia forsterana are of different size. Since the biggest bivalent in the Lepidoptera is usually the sex bivalent, these chromosomes are evidently an unequal sex chromosome pair which has not been recorded before in this order. The shorter sex chromosome is evidently the Y. The unequal sex chromosomes in Lozotaenia forsterana probably originated from a transverse break in the Y, which was earlier of the same size as the X, the break being followed by the disappearance of the smaller fragment. No unequal sex chromosome pair was found in closely related species. 1971 Hereditas