An Empirical Technique to Resolve Banding Sequences in Avian Chromosomes

Banding techniques are useful for marking specific regions of chromosomes, which otherwise exhibit morphological resemblances to a certain extent. C-banding, commonly called constitutive heterochromatin, is frequently used as an approach to resolve variations in terms of amount and distribution of heterochromatin among phylogenetically unrelated species. Another pattern i.e. G-banding is believed to mark the regions rich in guanine and cytosine that replicate DNA early in the synthesis phase of cell cycle. In the present communication, a simple technique has been described, to demonstrate banding sequences, conveniently by stressing chromosomal squash with an alkali, followed by saline treatment (C-band). G-bands can be obtained by exposing metaphase plates to trypsin for a controlled time period before staining with Giemsa-buffer solution. Certain measures have been taken to overcome difficulties, that generally arise, in demonstration of chromosomal bands