A high-resolution G-banding idiogram of Rattus norvegicus chromosomes.

G-banded karyotypes of Rattus norvegicus fibroblast cells at the late prophase, prometaphase, early metaphase, mid and late metaphase, and diagrammatic representation of the banding patterns at the 450-band level are presented. High-resolution G-banded rat chromosomes were prepared following the actinomycin D pretreatment technique. Silver-stained nucleolus organizer regions (Ag-NORS) were found in chromosome pairs 3, 11 and 12 of the rat karyotype.

Stability of cytogenetic alterations in a human melanoma cell line and five clonal derivatives.

A cytogenetic study was done on a human malignant melanoma cell line and its 5 clones. Chromosome banding analysis indicated the presence of 7 "shared" markers (M) and 9 unique markers (m) that were present only in the clones. Chromosomes 1, 5, 9, 12, 17 and 21 were involved in M-markers and chromosomes 1, 2, 4, 6, 8, 9, 11, 16, 17, 18 and 21 were involved in m-marker formation. Both parental and clonal lines had near-triploid chromosome numbers. A number of M-markers were isochromosomes of the short (p) and long (q) arms of chromosome 1. Our cytogenetic data indicate that the parental line contained subpopulations of cells that were in different stages of karyotypic evolution.

[Chromosome complements of eleven bird species of the orders columbiformes, passeriformes and tinamiformes (author's transl)]. / Estudo do complemento cromossómico de 11 espécies de aves das ordens columbiformes, passeriformes e tinamiformes.

The chromosome complements of 11 species of birds from the Columbiformes, Passeriformes and Tinamiformes Orders are described. Their karyotypes' evolution are discussed and pericentric inversions, centric fissions and/or fusions seem to have been of great importance. Banding patterns in the several Orders will be of great importance to know better the mechanisms of chromosomal evolution.