News and Views Hominoid phylogeny: inferences from a sub-terminal minisatellite analyzed by repeat expansion detection (RED) Amos S. Deinard Departments of Anthropology and Genetics, Y ale University, New Haven, CT, U.S.A. E-mail: asdeinard@ucdavis.edu Giorgio Sirugo & Kenneth K. Kidd Department of Genetics, Yale University, New Haven, CT, U.S.A. Journal of Human Evolution (1998) 35, 313–317 Article No. hu980245 Introduction Phylogenetic relationships among the African apes ( Pan and Gorilla) and humans continue to be hotly debated despite their being among the more thoroughly studied questions within the field of molecular sys- tematics. The lack of consensus stems from different molecular data sets yielding contra- dictory conclusions: data sets exist that support a Pan–Homo ,a Pan–Gorilla, or a H omo–Gorilla clade. In an effort to resolve the discrepancies among the different data sets, Ruvolo (1997) has recently evaluated all the available DNA sequence data with respect to the alternative phylogenetic hypotheses via a likelihood ratio test ( Wu, 1991 ). The resulting conclusion was that the data ‘‘provide overwhelming and su fficient support for a human–chimpanzee clade: no additional data sets need to be generated for the purpose of estimating hominoid phylogeny’’ ( Ruvolo, 1997 : 248). Although comprehensive with respect to available DNA sequence data, Ruvolo’s analysis nevertheless ignores a substantial and highly informative genetic data set: the cytogenetic evidence linking Pan and Gorilla as sister taxa. Specifically, both Pan and Gorilla exhibit heavily staining terminal bands (i.e., heterochromatin) on metaphase chromosomes that are not observed within either Homo or Pongo ( Marks, 1982 ; Stanyon & Chiarelli, 1982 ; Yunis & Prakash, 1982 ; Marks, 1993 ). These termi- nally located bands have been classified as both C-bands and G-bands, suggesting that they are both C-positive and G-positive staining regions of DNA (e.g. Yunis & Prakash, 1982 ; Marks, 1993 ; Royle et al ., 1994 ). It has been argued that these termi- nal bands represent a complex genetic trait among the African apes and provides genetic evidence for a Pan–Gorilla clade ( Stanyon, 1992 ; Marks, 1993 ). Ruvolo’s examination of the genetic data, of course, is certainly not the only comprehensive genetic review to overlook the cytogenetic data. Stanyon (1992) has argued that the omission of cytogenetic data from phylogenetic studies, especially those involving the human species, usually is based on the assumption that the exact genetic homology of chromo- somal bands cannot be demonstrated across species and therefore the existence of such bands could be evolutionary convergences. Consequently, if the exact genetic make-up of these shared terminal bands could be determined, the degree to which they are phylogenetically informative could be more accurately evaluated. Recently, Royle et al . (1994) used a telomere-anchored PCR strategy to deter- mine that the terminally located chromo- some bands within the chimpanzee are composed of (at least in part by) a repeated 32 bp sequence (i.e., a minisatellite). They Current address and address for correspondence and reprints: Amos S. Deinard, Class of 2001, School of Veterinary Medicine, Dean’s Office—Student Pro- grams, University of California, Davis, CA 95616. 0047–2484/98/090313+05 $30.00/0  1998 Academic Press