Phylogeography and Genetic Ancestry of Tigers (Panthera tigris)

Eight traditional subspecies of tiger (Panthera tigris), of which three recently became extinct, are commonly recognized on the basis of geographic isolation and morphological characteristics. To investigate the species' evolutionary history and to establish objective methods for subspecies recognition, voucher specimens of blood, skin, hair, and/or skin biopsies from 134 tigers with verified geographic origins or heritage across the whole distribution range were examined for three molecular markers: (1) 4.0 kb of mitochondrial DNA (mtDNA) sequence; (2) allele variation in the nuclear major histocompatibility complex class II DRB gene; and (3) composite nuclear microsatellite genotypes based on 30 loci. Relatively low genetic variation with mtDNA, DRB, and microsatellite loci was found, but significant population subdivision was nonetheless apparent among five living subspecies. In addition, a distinct partition of the Indochinese subspecies P. t. corbetti into northern Indochinese and Malayan Peninsula populations was discovered. Population genetic structure would suggest recognition of six taxonomic units or subspecies: (1) Amur tiger P. t. altaica; (2) northern Indochinese tiger P. t. corbetti; (3) South China tiger P. t. amoyensis; (4) Malayan tiger P. t. jacksoni, named for the tiger conservationist Peter Jackson; (5) Sumatran tiger P. t. sumatrae; and (6) Bengal tiger P. t. tigris. The proposed South China tiger lineage is tentative due to limited sampling. The age of the most recent common ancestor for tiger mtDNA was estimated to be 72,000–108,000 y, relatively younger than some other Panthera species. A combination of population expansions, reduced gene flow, and genetic drift following the last genetic diminution, and the recent anthropogenic range contraction, have led to the distinct genetic partitions. These results provide an explicit basis for subspecies recognition and will lead to the improved management and conservation of these recently isolated but distinct geographic populations of tigers

Disparate Phylogeographic Patterns of Molecular Genetic Variation in Four Closely Related South American Small Cat Species

Tissue specimens from four species of Neotropical small cats (Oncifelis geoffroyi, N = 38; O. guigna,N = 6; Leopardus tigrinus, N = 32; Lynchailurus colocolo, N = 22) collected from throughout their distribution were examined for patterns of DNA sequence variation using three mitochondrial genes, 16S rRNA, ATP8, and NADH-5. Patterns between and among O. guigna and O. geoffroyi individuals were assessed further from size variation at 20 microsatellite loci. Phylogenetic analyses using mitochondrial DNA sequences revealed monophyletic clustering of the four species, plus evidence of natural hybridization between L. tigrinus and L. colocolo in areas of range overlap and discrete population subdivisions reflecting geographical isolation. Several commonly accepted subspecies partitions were affirmed for L. colocolo, but not for O. geoffroyi. The lack of geographical substructure in O. geoffroyi was recapitulated with the microsatellite data, as was the monophyletic clustering of O. guigna and O. geoffroyi individuals. L. tigrinus forms two phylogeographic clusters which correspond to L.t. oncilla (from Costa Rica) and L.t. guttula (from Brazil) and which have mitochondrial DNA (mtDNA) genetic distance estimates comparable to interspecific values between other ocelot lineage species. Using feline-specific calibration rates for mitochondrial DNA mutation rates, we estimated that extant lineages of O. guigna diverged 0.4 million years ago (Ma), compared with 1.7 Ma for L. colocolo, 2.0 Ma for O. geoffroyi, and 3.7 Ma for L. tigrinus

Lost populations and preserving genetic diversity in the lion Panthera leo: Implications for its ex situ conservation

The original publication is available at www.springerlink.comTwo of the eight recognized lion subspecies, North African Barbary lion (Panthera leo leo) and South African Cape lion (Panthera leo melanochaita), have become extinct in the wild in the last 150 years. Based on sequences of mitochondrial DNA (mtDNA) control region (HVR1) extracted from museum specimens of four Barbary and one Cape lion, the former was probably a distinct population characterized by an invariable, unique mtDNA haplotype, whilst the latter was likely a part of the extant southern African lion population. Extinction of the Barbary line, which may still be found in "generic" zoo lions, would further erode lion genetic diversity. Therefore, appropriate management of such animals is important for maintaining the overall genetic diversity of the species. The mtDNA haplotype unique to the Barbary lion, in combination with the small size of the HVR1 analyzed (c. 130 bp), makes it possible and cost-effective to identify unlabelled Barbary specimens kept in museums and "generic" captive lions that may carry the Barbary line. An initial study of five samples from the lion collection of the King of Morocco, tested using this method, shows that they are not maternally Barbary. © Springer 2006.Ross Barnett, Nobuyuki Yamaguchi, Ian Barnes and Alan Coope

EFFECT OF PARTIAL METAL REDUCTION ON THE CATALYTIC PROPERTY OF FE/SIO2 IN CO HYDROGENATION

Effect of partial metal reduction on the property of supported iron catalysts has been studied using 9.1 wt% Fe/SiO2 as a model catalyst and CO hydrogenation as a test reaction. The extent of iron reduction does not alter the intrinsic activity of iron nor distribution of the hydrocarbon products with specific carbon numbers, but significantly changes the olefin/paraffin ratio among the products. This kinetic behavior agrees with the result of gas chemisorption that the H2/CO adsorption ratio decreases as the catalyst is reduced poorly. Well-reduced iron catalysts deactivate during the reaction because the carbon species deposited on the surface gradually transform into less-reactive ones as observed in the TPSR experimentsclose1

Phylogenetic Relationships among Tigers from mtDNA Haplotypes

<div><p>(A) Phylogenetic relationships based on MP among the tiger mtDNA haplotypes from the combined 4,078 bp mitochondrial sequence (<a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.0020442#pbio-0020442-t002" target="_blank">Table 2</a>). Branches of the same color represent haplotypes of the same subspecies. Trees derived from ME and ML analyses have identical topologies. Numbers above branches represent bootstrap support from 100 replicates using the MP method, followed by bootstrap values using the ME-ML analyses (only those over 70% are indicated). Numbers below branches show number of MP steps per number of homoplasies from a strict consensus tree. Numbers in parentheses represent numbers of individuals sharing the same haplotype. MP analysis using heuristic search and tree-bisection-reconnection branch-swapping approach results in two equally most-parsimonious trees and the one resembling the ME and ML trees is shown here (tree length = 60 steps; CI = 0.900). The ME tree is constructed with PAUP using Kimura two-parameter distances (transition to transversion ratio = 2) and NJ algorithm followed by branch-swapping procedure (ME = 0.0142). The ML approach is performed using a TrN (Tamura-Nei) +I (with proportion of invariable sites) model, and all nodes of the ML tree were significant (a consensus of 100 trees, –Ln likelihood = 5987.09).</p> <p>(B) Statistical parsimony network of tiger mtDNA haplotypes based on 4,078 mtDNA sequences constructed using the TCS program (<a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.0020442#pbio-0020442-Clement1" target="_blank">Clement et al. 2000</a>). The area of the circle is approximately proportional to the haplotype frequency, and the length of connecting lines is proportional to the exact nucleotide differences between haplotypes with each unit representing one nucleotide substitution. Missing haplotypes in the network are represented by dots. Haplotype codes and the number of individuals (in parentheses) with each haplotype are shown (see <a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.0020442#pbio-0020442-t002" target="_blank">Table 2</a>).</p></div

Historic and Current Geographic Distribution of Tigers Corresponding to the Eight Traditional Subspecies Designation

<p>Geographic origin of samples and sample size (circles or squares) from each location are indicated (see <a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.0020442#pbio-0020442-t301" target="_blank">Table 3</a> for sources). Three-letter codes (TIG, ALT, etc.) are indicated subspecies abbreviations. Dotted lines are approximate boundaries between tiger subspecies studied here. The Isthmus of Kra divides the traditional Indochinese tigers into the northern Indochinese tigers <i>P. t. corbetti</i> I and the Malayan tigers <i>P. t. corbetti</i> II based on the present study. We propose the Malayan tiger subspecies, COR II, be named <i>P. t. jacksoni,</i> to honor Peter Jackson, the former Chair of the IUCN's Cat Specialist Group who has contributed significantly to worldwide tiger conservation.</p

Schematic of P. tigris mtDNA

<p>The position of PCR primers used for amplification of Cymt specific sequences and alignment of the homologous Numt sequence (outer, dashed line) in tiger mitochondria. Fifteen Cymt-specific primer sets spanning 6,026 bp of mtDNA were designed and screened for polymorphism in tigers (inner, solid line). Five indicated segments showed no variation among fifteen tigers that represented five traditional subspecies and therefore were excluded from further analysis. The ten variable segments (4,078 bp) were amplified in 100 tiger individuals. Primer sequences are listed in <a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.0020442#pbio-0020442-t001" target="_blank">Table 1</a>. Diamonds indicate polymorphic mtDNA segments; brackets indicate monomorphic mtDNA segments among tigers that were excluded from phylogenetic analysis.</p