Somatic chromosomes of black-headed oriole,Oriolus xanthornus (Linn.): A probable case of translocation heterozygosity

Summary 2n=80. There are 7 pairs of macrochromosomes in the male karyotype. In 2 females, besides the sex chromosomes, chromosome 3 and the largest microchromosome are unpaired and there is an additional large unpaired macrochromosome. This aberrant karyotype is best interpreted in terms of a reciprocal translocation heterozygosity, in all likelihood, at the population level.Acknowledgment. We thank Prof. U.S. Srivastava, Zoology Department, Allahabad University, for providing facilities. Financial assistance from CSIR, India in the form of a Senior Research Fellowship to one of us (H.A.A.) is thankfully acknowledged.