DIFFERENCES IN THE DISTRIBUTION AND NATURE OF THE INTERSTITIAL TELOMERIC (TTAGGG)(N) SEQUENCES IN THE CHROMOSOMES OF THE GIRAFFIDAE, OKAPI (OKAPIA-JOHNSTONI), AND GIRAFFE (GIRAFFA-CAMELOPARDALIS) - EVIDENCE FOR ANCESTRAL TELOMERES AT THE OKAPI POLYMORPHIC ROB(4-26) FUSION SITE

Intrachromosomal telomeric sequences (TTAGGG)n were analyzed in the tw o members of the family Giraffidae, the giraffe and the okapi. The gir affe has a diploid chromosome number of 2n = 30, whereas the okapi chr omosome number varies from 2n = 46 to 2n = 45 and 2n = 44 due to a ''r ecent'' Robertsonian fusion event. The interstitial telomeres that we detected in these species are of two types: (1) In the okapi, a long i nterstitial telomeric element is present at the fusion site of the rob (4;26). The nature of this interstitial telomeric element suggests tha t it is a remnant of the telomeres of the ancestral chromosomes that p articipated in the fusion event. (2) In the giraffe, short stretches o r degenerate telomeric sequences which are part of the satellite DNA a re present at intrachromosomal sites. The results of this study provid e insights into the origin of interstitial telomeric sequences in the Giraffidae.