Improving beetle karyotype analysis restriction endonuclease banding of tenebrio molitor chromosomes

Abstract

Fixed mitotic chromosomes of Tenebrio molitor have been analysed by means of C-banding and by digestion with fcoRI and AluI restriction endonucleases. The chromosomal morphology, ambiguous after conventional staining or C-banding, is much improved by digestion with restriction endonucleases. AluI gives a banding pattern similar to that obtained by C-banding, while EcoRI induces a reverse banding pattern with respect to the previous ones. The EcoRI digestion pattern of chromosomes is probably produced by extraction of a pericentromeric and equilocated highly repeated DNA. In this species, it seems that neither the compaction of the heterochromatin nor the size of the restriction target (six base pairs (bp) for EcoRI) have any effect on the amount of removable DNA. Also, a chromosomal heteromorphism for pair number 9 due to a pericentric inversion has been found in one individual by means of EcoRI treatment, that was cryptic by the other banding techniques. © 1990, The Genetical Society of Great Britain.