DNA composition in South American camelids. I. Characterization and in situ hybridization of satellite DNA fractions.

The DNA composition and the in situ hybridization of satellite fractions were analysed in the New World camelids llama, alpaca, guanaco and vicuña. In the four camelid forms, it was possible to identify a similar main band DNA and five satellite fractions (I-V) with G + C base contents ranging from 32% to 66%. Satellites II-V from llama were in situ reannealed on chromosomes from the four camelid forms. The results obtained were: (a) the four satellites hybridized with regions of C-banding (centromeric regions of all chromosomes and short arms of some autosomes); (b) in general, homologous hybridizations (llama DNA versus llama chromosomes) were more efficient than heterologous reassociations; there were however three exceptions to this rule (vicuña and alpaca satellite fraction II, chromosome group B; vicuña fraction V, chromosome groups A and B); (c) X chromosomes from the four camelids had satellites III-V but lacked satellite II, (d) no satellite fraction was detected on chromosome Y. The analysis of the in situ hybridization patterns allowed to conclude that most or all C-banded chromosome regions comprise several satellite DNA fractions. It is, moreover, proposed that there is an ample interspecies variation in the number of chromosomes that cross-react with a given satellite fraction. Our data give further support to the close genomic kinship of New World camelids.