Joan C. Menninger

Atlas of Mammalian Chromosomes

Foreword. Preface. Acknowledgments. MONOTREMATA. Order Monotremata. MARSUPIALIA. Order Didelphimorphia. Order Paucituberculata. Order Microbiotheria. Order Dasyuromorphia. Order Peramelemorphia. Order Notoryctemorphia. Order Diprotodontia. AFROTHERIA. Order Afrosoricida. Order Macroscelidea. Order Sirenia. Order Proboscidea. Order Hyracoidea. Order Tubulidentata. XENARTHRA. Order Xenarthra. EUARCHONTOGLIRES. Order Scandentia. Order Dermoptera. Order Primates. Order Rodentia. Order Lagomorpha. LAURASIATHERIA. Order Eulipotyphla. Order Chiroptera. Order Carnivora. Order Pholidota. Order Cetartiodactyla. Order Perissodactyla.

Molecular evidence for species-level distinctions in clouded leopards.

Among the 37 living species of Felidae, the clouded leopard (Neofelis nebulosa) is generally classified as a monotypic genus basal to the Panthera lineage of great cats. This secretive, mid-sized (16-23 kg) carnivore, now severely endangered, is traditionally subdivided into four southeast Asian subspecies (Figure 1A). We used molecular genetic methods to re-evaluate subspecies partitions and to quantify patterns of population genetic variation among 109 clouded leopards of known geographic origin (Figure 1A, Tables S1 ans S2 in the Supplemental Data available online). We found strong phylogeographic monophyly and large genetic distances between N. n. nebulosa (mainland) and N. n. diardi (Borneo; n = 3 individuals) with mtDNA (771 bp), nuclear DNA (3100 bp), and 51 microsatellite loci. Thirty-six fixed mitochondrial and nuclear nucleotide differences and 20 microsatellite loci with nonoverlapping allele-size ranges distinguished N. n. nebulosa from N. n. diardi. Along with fixed subspecies-specific chromosomal differences, this degree of differentiation is equivalent to, or greater than, comparable measures among five recognized Panthera species (lion, tiger, leopard, jaguar, and snow leopard). These distinctions increase the urgency of clouded leopard conservation efforts, and if affirmed by morphological analysis and wider sampling of N. n. diardi in Borneo and Sumatra, would support reclassification of N. n. diardi as a new species (Neofelis diardi).

Comparative Genomics: Tracking Chromosome Evolution in the Family Ursidae Using Reciprocal Chromosome Painting

The Ursidae family includes eight species, the karyotype of which diverges somewhat, in both chromosome number and morphology, from that of other families in the order Carnivora. The combination of consensus molecular phylogeny and high-resolution trypsin G-banded karyotype analysis has suggested that ancestral chromosomal fissions and at least two fusion events are associated with the development of the different ursid species. Here, we revisit this hypothesis by hybridizing reciprocal chromosome painting probes derived from the giant panda (Ailuropoda melanoleuca), domestic cat (Felis catus), and man (Homo sapiens) to representative bear species karyotypes. Comparative analysis of the different chromosome segment homologies allowed reconstruction of the genomic composition of a putative ancestral bear karyotype based upon the recognition of 39 chromosome segments defined by painting as the smallest conserved evolutionary unit segments (pSCEUS) among these species. The different pSCEUS combinations occurring among modern bear species support and extend the postulated sequence of chromosomal rearrangements and provide a framework to propose patterns of genome reorganization among carnivores and other mammal radiations.

The Pattern of Phylogenomic Evolution of the Canidae

Canidae species fall into two categories with respect to their chromosome composition: those with high numbered largely acrocentric karyotypes and others with a low numbered principally metacentric karyotype. Those species with low numbered metacentric karyotypes are derived from multiple independent fusions of chromosome segments found as acrocentric chromosomes in the high numbered species. Extensive chromosome homology is apparent among acrocentric chromosome arms within Canidae species; however, little chromosome arm homology exists between Canidae species and those from other Carnivore families. Here we use Zoo-FISH (fluorescent in situ hybridization, also called chromosomal painting) probes from flow-sorted chromosomes of the Japanese raccoon dog (Nyctereutes procyonoides) to examine two phylogenetically divergent canids, the arctic fox (Alopex lagopus) and the crab-eating fox (Cerdocyon thous). The results affirm intra-canid chromosome homologies, also implicated by G-banding. In addition, painting probes from domestic cat (Felis catus), representative of the ancestral carnivore karyotype (ACK), and giant panda (Ailuropoda melanoleuca) were used to define primitive homologous segments apparent between canids and other carnivore families. Canid chromosomes seem unique among carnivores in that many canid chromosome arms are mosaics of two to four homology segments of the ACK chromosome arms. The mosaic pattern apparently preceded the divergence of modern canid species since conserved homology segments among different canid species are common, even though those segments are rearranged relative to the ancestral carnivore genome arrangement. The results indicate an ancestral episode of extensive centric fission leading to an ancestral canid genome organization that was subsequently reorganized by multiple chromosome fusion events in some but not all Canidae lineages.

The feline major histocompatibility complex is rearranged by an inversion with a breakpoint in the distal class I region

In order to determine the genomic organization of the major histocompatibility complex (MHC) of the domestic cat (Felis catus), DNA probes for 61 markers were designed from human MHC reference sequences and used to construct feline MHC BAC contig map spanning ARE1 in the class II region to the olfactory receptor complex in the extended class I region. Selected BAC clones were then used to identify feline-specific probes for the three regions of the mammalian MHC (class II–class III–class I) for radiation hybrid mapping and fluorescent in situ hybridization to refine the organization of the domestic cat MHC. The results not only confirmed that the p-arm of domestic cat B2 is inverted relative to human Chromosome 6, but also demonstrated that one inversion breakpoint localized to the distal segment of the MHC class I between TRIM39 and TRIM26. The inversion thus disjoined the ~2.85 Mb of MHC containing class II–class III–class I (proximal region) from the ~0.50 Mb of MHC class I/extended class I region, such that TRIM39 is adjacent to the Chromosome B2 centromere and TRIM26 is adjacent to the B2 telomere in the domestic cat.

Insertional Polymorphisms of Endogenous Feline Leukemia Viruses

ABSTRACT The number, chromosomal distribution, and insertional polymorphisms of endogenous feline leukemia viruses (enFeLVs) were determined in four domestic cats (Burmese, Egyptian Mau, Persian, and nonbreed) using fluorescent in situ hybridization and radiation hybrid mapping. Twenty-nine distinct enFeLV loci were detected across 12 of the 18 autosomes. Each cat carried enFeLV at only 9 to 16 of the loci, and many loci were heterozygous for presence of the provirus. Thus, an average of 19 autosomal copies of enFeLV were present per cat diploid genome. Only five of the autosomal enFeLV sites were present in all four cats, and at only one autosomal locus, B4q15, was enFeLV present in both homologues of all four cats. A single enFeLV occurred in the X chromosome of the Burmese cat, while three to five enFeLV proviruses occurred in each Y chromosome. The X chromosome and nine autosomal enFeLV loci were telomeric, suggesting that ectopic recombination between nonhomologous subtelomeres may contribute to enFeLV distribution. Since endogenous FeLVs may affect the infectiousness or pathogenicity of exogenous FeLVs, genomic variation in enFeLVs represents a candidate for genetic influences on FeLV leukemogenesis in cats.