Fig. 1

Gel electrophoresis following PCR for zebra finch blood samples. Single bands were obtained for a male at 242 bp and double bands at 242 and 179 bp for a female performed using (a) 2% agarose gel and (b) 8% polyacrylamide gel respectively; each lane beginning from the marker to the edge of the gel represents double, single, half and one fourth Whatman filter paper disc respectively for both male and female sample. Separate sets of samples were run on agarose and polyacrylamide gels respectively, to demonstrate better band separation of the PCR product obtained from female zebra finch genomic DNA sample by using the latter electrophoresis method. c PCR products from crow tissue samples showing a single band at 390 bp for ZZ chromosomes of males and double bands at 390 and 460 bp for Z and W chromosomes for females. d A single band was obtained for the delta opioid receptor gene at 120 bp for both male and female zebra finches