Localization of rDNA and Giemsa-banded chromosome complement of white-handed gibbon, Hylobates lar.

A karyotype based on banding pattern and chromosome length is presented for the white-handed gibbon, Hylobates lar. Little homology with the banding patterns of the chromosomes of the other Hominoidea can be seen, confirming the early evolutionary separation of Hylobatidae and the other apes. Hybridization in situ with ribosomal RNA shows that the secondary constriction of a submetacentric chromosome (15) is the only site of the nucleolar organizer, as in the Cercopithecoidea. The correlation of polymorphic variation in size of this secondary constriction with grain density suggests differences in the number of gene copies per chromosome.