C-heterochromatin content of supernumerary chromosome segments of grasshoppers: detection of an euchromatic extra segment

• Published in: Heredity Vol. 53; no. 1; pp. 167 - 175
• Main Authors: Camacho, J.P.M, Viseras, E, Navas, J, Cabrero, J
• Format: Journal Article
• Language: English
• Published: Basingstoke Nature Publishing 01-01-1984
• Subjects: Acrididae; animal breeding; animal genetics; Animals; arthropods; Biological and medical sciences; Cytogenetics; entomology; Fundamental and applied biological sciences. Psychology; Genetics of eukaryotes. Biological and molecular evolution; Insecta; Invertebrata; Invertebrates; Morphology. Histology. Cytology; Heterochromatin; Arthropoda; Insecta; Orthoptera; Cytogenetics; Accessory B chromosome; Invertebrata
• ISSN: 0018-067X; 1365-2540
• DOI: 10.1038/hdy.1984.72

The response of 11 supernumerary segments to C-banding has been compared in six species of grasshoppers. A unique euchromatic supernumerary segment was present in the five populations of Omocestus bolivari analysed. It appears negatively heteropycnotic during the first prophase of meiosis and does not C-band. This euchromatic segment is distally located in the M sub(6) chromosome and in every case was present in a heterozygous condition. Four additional types of heterochromatic supernumerary chromosome segments may be distinguished in grasshoppers by C-banding. All five types of segment appear to affect chiasma distribution in heterozygous monochiasmate bivalents but only those heterochromatic segments that do not C-band influence mean cell chiasma frequency.