Human chromosome 7 has a complex syntenic origin. It was divided into two segments in both the ancestral primate karyotype and in Platyrrhini. Apparently, a small segment in the ancestral platyrrhine karyotype was associated with HSA5 and the remainder formed a middle-sized submetacentric. We tested the dynamics of platyrrhine chromosomes by hybridizing the locus specific Willams-Beuren probe (7q 11.23, 450 kb) to chromosomes of representative species from the three families of the New World monkeys recently proposed by molecular genomics: Cebidae, Callithrix argentata (bare ear marmoset or silvery marmoset, 2n = 44); Pitheciidae, Callicebus cupreus [red titi monkey, or coppery monkey, 2n = 46)] and Atelidae, Alouatta caraya (black and gold howler, 2n = 52). In both the marmoset and the howler monkeys, the signal was found on the small segment of chromosome 7 associated with human chromosome 5, but not in Callicebus cupreus. Instead, the Williams-Beuren syndrome (WS) signal was found on a C. cupreus chromosome previously reported to be hybridized only by human chromosome 1. The WS probe indicates a small, but complex translocation never described before. Our results point out that fluorescence in situ hybridization (FISH) with locus specific probes and cloned DNA fragments such as bacterial aftificial chromosomes (BACs) provides higher resolution than FISH with whole chromosomes paints. It may be well that the variability seen in the hybridization patterns and revealed by the WS FISH in this report is as a result of a rearrangement 'hot spot'. The WS region in humans is composed of region-specific different blocks of complex segmental duplications that probably promote the extraordinary rate of evolutionary dynamics of this region among primate species, and which continues to be reflected today by the predisposition of this region to disease syndromes such as WS. The evolutionary history of this region also suggests that repeat families in this region had their origin in a common ancestor of both Old World and New World monkeys.
|Numero di pagine||6|
|Rivista||Journal of Zoological Systematics and Evolutionary Research|
|Stato di pubblicazione||Published - 2007|
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