A South African endemic antelope, the Grey Rhebok (Pelea capreolus), has long been an evolutionary enigma in bovid systematics-its phylogenetic intractability attributed to its curious combination of derived and primitive morphological attributes and the consequences of a rapid radiation. By using a combination of DNA sequences, chromosomal characteristics and quantitative and qualitative morphological features we show that the species is a sister taxon to a clade that comprises the waterbuck, reedbuck and allies. Our finding of few unambiguous synapomorphies reinforces suggestions of a rapid radiation and highlights the effects of incomplete lineage sorting, including the hemiplasic nature of several chromosomal rearrangements. We investigate these data to address the general question of what may have led to Pelea being both genetically and ecologically distinct from the Reduncini. We argue that its adaptation to exposed habitats, free of standing water, arose by vicariance prompted by increasing aridity of the extreme south/southwestern region of the African continent in the Miocene. Ancestral lineages leading to the extant Redunca and Kobus, on the other hand, retreated to water-abundant refugia in the north during these mostly globally cool phases. The mosaic of water-rich environments provided by the Okavango and the drainage systems in the southwestern extension of the East African Rift system are considered to have facilitated speciation and chromosomal evolution within these antelope.

• MeSH
• antilopy genetika   MeSH
• biologická evoluce MeSH
• chromozom Y MeSH
• ekosystém MeSH
• fylogeneze * MeSH
• hybridizace in situ fluorescenční MeSH
• malování chromozomů MeSH
• mitochondriální DNA MeSH
• molekulární sekvence - údaje MeSH
• skot MeSH
• vznik druhů (genetika) * MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• skot MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• mitochondriální DNA MeSH

Equidae is a small family which comprises horses, African and Asiatic asses, and zebras. Despite equids having diverged quite recently, their karyotypes underwent rapid evolution which resulted in extensive differences among chromosome complements in respective species. Comparative mapping using whole-chromosome painting probes delineated genome-wide chromosome homologies among extant equids, enabling us to trace chromosome rearrangements that occurred during evolution. In the present study, we performed subchromosomal comparative mapping among seven Equidae species, representing the whole family. Region-specific painting and bacterial artificial chromosome probes were used to determine the orientation of evolutionarily conserved segments with respect to centromere positions. This allowed assessment of the configuration of all fusions occurring during the evolution of Equidae, as well as revealing discrepancies in centromere location caused by centromere repositioning or inversions. Our results indicate that the prevailing type of fusion in Equidae is centric fusion. Tandem fusions of the type telomere-telomere occur almost exclusively in the karyotype of Hartmann's zebra and are characteristic of this species' evolution. We revealed inversions in segments homologous to horse chromosomes 3p/10p and 13 in zebras and confirmed inversions in segments 4/31 in African ass, 7 in horse and 8p/20 in zebras. Furthermore, our mapping results suggested that centromere repositioning events occurred in segments homologous to horse chromosomes 7, 8q, 10p and 19 in the African ass and an element homologous to horse chromosome 16 in Asiatic asses. Centromere repositioning in chromosome 1 resulted in three different chromosome types occurring in extant species. Heterozygosity of the centromere position of this chromosome was observed in the kiang. Other subtle changes in centromere position were described in several evolutionary conserved chromosomal segments, suggesting that tiny centromere repositioning or pericentric inversions are quite frequent in zebras and asses.

• MeSH
• centromera genetika   metabolismus   MeSH
• chromozomální inverze MeSH
• druhová specificita MeSH
• Equidae klasifikace   genetika   MeSH
• genová přestavba MeSH
• hybridizace in situ fluorescenční MeSH
• karyotyp * MeSH
• malování chromozomů metody   MeSH
• mapování chromozomů MeSH
• molekulární evoluce * MeSH
• telomery genetika   MeSH
• umělé bakteriální chromozomy MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Cross-species chromosome painting has been applied to most of the species making up the numerically small family Equidae. However, comparative mapping data were still lacking in Asiatic asses kulan (Equus hemionus kulan) and kiang (E. kiang). The set of horse arm-specific probes generated by laser microdissection was hybridized onto kulan (E. hemionus kulan) and kiang (E. kiang) chromosomes in order to establish a genome-wide chromosomal correspondence between these Asiatic asses and the horse. Moreover, region-specific probes were generated to determine fusion configuration and orientation of conserved syntenic blocks. The kulan karyotype (2n = 54) was ascertained to be almost identical to the previously investigated karyotype of onager E. h. onager (2n = 56). The only difference is in fusion/fission of chromosomes homologous to horse 2q/3q, which are involved in chromosome number polymorphism in many Equidae species. E. kiang karyotype differs from the karyotype of E. hemionus by two additional fusions 8q/15 and 7/25. Chromosomes equivalent to 2q and 3q are not fused in kiang individuals with 2n = 52. Several discrepancies in centromere positions among kulan, kiang and horse chromosomes have been described. Most of the chromosome fusions in Asiatic asses are of centromere-centromere type. Comparative chromosome painting in kiang completed the efforts to establish chromosomal homologies in all representatives of the family Equidae. Application of region-specific probes allows refinement comparative maps of Asiatic asses.

• MeSH
• DNA sondy chemie   MeSH
• druhová specificita MeSH
• Equidae genetika   MeSH
• hybridizace in situ fluorescenční MeSH
• karyotypizace MeSH
• koně genetika   MeSH
• malování chromozomů MeSH
• mapování chromozomů MeSH
• metafáze MeSH
• pruhování chromozomů MeSH
• savčí chromozomy genetika   ultrastruktura   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Názvy látek
• DNA sondy MeSH

Using laser microdissection we prepared a set of horse chromosome arm-specific probes. Most of the probes were generated from horse chromosomes, some of them were derived from Equus zebra hartmannae. The set of probes were hybridized onto E. grevyi chromosomes in order to establish a genome-wide chromosomal correspondence between this zebra and horse. The use of arm-specific probes provided us with more information on the mutual arrangement of the genomes than we could obtain by means of whole-chromosome paints generated by flow sorting, even if we used reciprocal painting with probe sets from both species. By comparison of our results and results of comparative mapping in E. burchelli, we also established the chromosomal correspondence between E. grevyi and E. burchelli, providing evidence for a very close karyotypic relationship between these two zebra species. Establishment of the comparative map for E. grevyi contributes to the knowledge of the karyotypic phylogeny in the Equidae family.

• MeSH
• chromozomy ultrastruktura   MeSH
• DNA sondy chemie   MeSH
• druhová specificita MeSH
• Equidae MeSH
• hybridizace nukleových kyselin MeSH
• karyotypizace MeSH
• koně MeSH
• malování chromozomů MeSH
• mapování chromozomů MeSH
• metafáze MeSH
• modely genetické MeSH
• pruhování chromozomů MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• DNA sondy MeSH