Jorge Ortega

Male dominance, paternity, and relatedness in the Jamaican fruit‐eating bat (Artibeus jamaicensis)

We analysed variation at 14 nuclear microsatellite loci to assess the genetic structure, relatedness, and paternity of polygynous Jamaican fruit‐eating bats. A total of 84 adults captured in two caves exhibited little genetic differentiation between caves (FST = 0.008). Average relatedness among adult females in 10 harem groups was very low (R = 0.014 ± 0.011), providing no evidence of harem structure. Dominant and subordinate males shared paternity in large groups, while dominant and satellite males shared paternity in smaller groups. However, our results suggest that male rank influences paternity. Dominant males fathered 69% of 40 offspring, followed by satellite (22%) and subordinate males (9%). Overall adult male bats are not closely related, however, in large harem groups we found that subordinate and dominant males exhibited relatedness values consistent with a father‐offspring relationship. Because dominant and subordinate males also sired all the pups in large groups, we propose that their association provides inclusive fitness to them.

A reliable, non-invasive method for sex determination in the endangered San Joaquin kit fox (Vulpes macrotis mutica) and other canids

Jorge Ortega, Marı́a del Rosario Franco, Brice A. Adams, Katherine Ralls & Jesús E. Maldonado Genetics Program, National Museum of Natural History, Smithsonian Institution, 3001 Connecticut Ave., Washington, DC 20008, USA; Institute for Biodiversity and Ecosystem Dynamics (IBED), Zoological Museum – Section Vertebrates, University of Amsterdam, P.O. Box 94766, 1090 GT Amsterdam, The Netherlands; Department of Biology, University of Louisiana at Lafayette, P.O. Box 42451, Lafayette, LA 70504, USA; Conservation and Research Center, Smithsonian’s National Zoological Park, Washington, DC 20008, USA (Author for correspondence: fax: 202-673-4648; e-mail: artibeus2@aol.com)

Operational criteria for genetically defined species: analysis of the diversification of the small fruit-eating bats, Dermanura (Phyllostomidae: Stenodermatinae)

Species diversity and species limits of the small fruit-eating bats, genus Dermanura (Phyllostomidae: Stenodermatinae) were examined. Estimates of species diversity based on classical morphological criteria (current taxonomy) were compared to diversity estimates based on monophyly and cytochrome-b sequence divergence. The most recent taxonomic list included nine species, whereas the genetic based list contained 11: anderseni, azteca, bogotensis, cinerea, glauca, gnoma, phaeotis, rava, rosenbergi, tolteca, and watsoni, of which three (bogotensis Andersen, rava Miller, and rosenbergi Thomas) have been considered synonyms of cinerea, glauca, phaeotis, and tolteca by previous authors. In addition, we consider incomitata to be a synonym of watsoni. Phylogenetic analyses of mtDNA sequences resolved the interrelationships among taxa and prompted us to re-evaluate some morphological characters that support the distinction of all the recognized taxa, therefore providing a robust estimate of species status. A phylogenetic tree revealed a geographic component to the diversification of Dermanura, including a historical connection between western Andean and Middle American biota. In South America, no species has been recorded from both sides of the Andes Mountains, and at least one clade (glauca, gnoma, and bogotensis) is restricted to the eastern versant of the Andes. Using genetic data (monophyly and genetic distance) to identify species we were able to produce testable genealogical and biogeographic hypotheses to facilitate further studies.

Aggression and tolerance by dominant males of Artibeus jamaicensis: strategies to maximize fitness in harem groups

Abstract Strategies of males in harem-forming mammals may change depending on 2 variables, female group size and consequent ability of the harem male to monopolize copulations, and the relative costs and benefits of tolerating other males. We studied harems of 4–20 females associated with a dominant male in small groups of Artibeus jamaicensis (<14 females), and with dominant and subordinate males in large groups (>14 females). Dominant males displayed defensive behavior toward satellite males when they intruded into the roosting site. Small groups received the highest number of visits by satellite males, and dominant males did not display total defense of females. During the breeding season, females roosted in highly compacted clusters and dominant males were more active in their defensive behavior. Subordinate males were generally tolerated in harem groups and their presence reduced the number of adult male visits. Some young in large harem groups were sired by subordinate males, resulting in a genetic benefit for both dominant and subordinate males. Dominant males had the highest fitness in the large harem groups by sharing paternity with related subordinate males and by rejecting unrelated intruders.

Tamandua mexicana (Pilosa: Myrmecophagidae)

Abstract Tamandua mexicana (Saussure, 1860) is a medium-sized anteater commonly known as the northern tamandua or oso hormiguero. It has an elongated head and is toothless, with a slender and sticky tongue and a prehensile tail. Its fur has a black patch across the back like a vest worn backward against a pale yellow background. It is present from southern Mexico to the northwest Andes in South America; it also lives in many different forested ecosystems including transformed areas. The International Union for Conservation of Nature and Natural Resources classifies T. mexicana as “Least Concern” because it has a wide distribution, presumably large population, and because it is represented in protected areas, as well as anthropogenic ecosystems. In some areas local laws protect T. mexicana from exploitation and habitat destruction.

Anoura Geoffroyi (Chiroptera: Phyllostomidae)

Abstract Anoura geoffroyi Gray, 1838, is a phyllostomid bat commonly referred to as Geoffroys tailless bat. This bat is broadly distributed in the Neotropics from both versants of Mexico into northern and western South America and the Amazon Basin. A. geoffroyi eats mainly pollen, but also consumes fruit, nectar, and insects. It is not of special conservation concern because it is abundant throughout its range.

Vitronectin Expression in the Airways of Subjects with Asthma and Chronic Obstructive Pulmonary Disease

Vitronectin, a multifunctional glycoprotein, is involved in coagulation, inhibition of the formation of the membrane attack complex (MAC), cell adhesion and migration, wound healing, and tissue remodeling. The primary cellular source of vitronectin is hepatocytes; it is not known whether resident cells of airways produce vitronectin, even though the glycoprotein has been found in exhaled breath condensate and bronchoalveolar lavage from healthy subjects and patients with interstitial lung disease. It is also not known whether vitronectin expression is altered in subjects with asthma and COPD. In this study, bronchial tissue from 7 asthmatic, 10 COPD and 14 control subjects was obtained at autopsy and analyzed by immunohistochemistry to determine the percent area of submucosal glands occupied by vitronectin. In a separate set of experiments, quantitative colocalization analysis was performed on tracheobronchial tissue sections obtained from donor lungs (6 asthmatics, 4 COPD and 7 controls). Vitronectin RNA and protein expressions in bronchial surface epithelium were examined in 12 subjects who undertook diagnostic bronchoscopy. Vitronectin was found in the tracheobronchial epithelium from asthmatic, COPD, and control subjects, although its expression was significantly lower in the asthmatic group. Colocalization analysis of 3D confocal images indicates that vitronectin is expressed in the glandular serous epithelial cells and in respiratory surface epithelial cells other than goblet cells. Expression of the 65-kDa vitronectin isoform was lower in bronchial surface epithelium from the diseased subjects. The cause for the decreased vitronectin expression in asthma is not clear, however, the reduced concentration of vitronectin in the epithelial/submucosal layer of airways may be linked to airway remodeling.

Genetic variation in a peripheral and declining population of black-tailed prairie dogs (Cynomys ludovicianus) from Mexico

Abstract Across North America, anthropogenically induced habitat fragmentation has led to a severe decline in populations of black-tailed prairie dogs (Cynomys ludovicianus). Although the area occupied by black-tailed prairie dogs in Chihuahua, northwestern Mexico, also has recently declined, this site remains comparatively unaffected by human disturbance. Cytochrome-b sequences and 10 nuclear microsatellite loci were analyzed across 13 colonies to test if due to large size, absence of plague, and protected status, the black-tailed prairie dogs from Janos possess relatively high levels of genetic variation and low genetic structure; or if recent population decline and peripheral effects result in relatively low genetic variation and high genetic structure. Analysis suggests moderate mitochondrial genetic variation relative to other sciurids, and not significantly different nuclear genetic variation relative to other populations of prairie dogs. Furthermore, in accordance to black-tailed prairie dog social organization, genetic structure among local populations was significant, and within-colony variation was higher than among-colony variation for both markers. FST was higher for mitochondrial than for nuclear DNA related to female philopatry and male-biased gene flow. Finally, a negative correlation between genetic differentiation as a function of colony area and population size found for nuclear microsatellite loci suggests an increased effect of genetic drift in smaller and less-dense colonies because of recent habitat fragmentation. In conclusion, despite being a peripheral and declining population, Janos black-tailed prairie dogs retained genetic variation that has been maintained by their social structure and dispersal pattern. Resumen En Norte América, la fragmentación del hábitat inducida por el hombre ha provocado una reducción considerable de las poblaciones de perros llaneros de cola negra (Cynomys ludovicianus). Aunque el área ocupada por las colonias de perros llaneros en Chihuahua, al noroeste de México, también se ha reducido recientemente, esta población ha sido menos afectada por la perturbación humana. Se analizaron secuencias del citocromo b (Cytb) y 10 microsatélites nucleares en 13 colonias para poner a prueba si la población de perros llaneros de cola negra de Janos posee niveles de variación genética relativamente altos y baja estructura genética debido a su gran tamaño, ausencia de peste y estatus de protección; o si la disminución poblacional reciente y los efectos periféricos han resultado en la presencia de baja variación y alta estructura genética. Los análisis sugieren que la variación genética mitocondrial es moderada con relación a otros sciúridos y que la variación genética nuclear no es significativamente distinta en relación a otras poblaciones de perros llaneros. Además, de acuerdo con la organización social de los perros llaneros de cola negra, la estructura genética entre poblaciones locales fue significativa y la variación hacia el interior de las colonias fue mayor que entre las colonias para ambos marcadores. Con relación a la filopatría de las hembras y la dispersión sesgada hacia los machos, la FST fue mayor para el ADN mitocondrial que para el ADN nuclear. Finalmente, para los marcadores nucleares se encontró una correlación negativa entre la diferenciación genética y el área de la colonia y el tamaño poblacional, lo que sugiere un incremento en el efecto de la deriva génica en las colonias más pequeñas y menos densas como resultado de la fragmentación del hábitat reciente. En conclusión, la estructura social y el patrón de dispersión ha mantenido la variación genética de los perros llaneros de cola negra de Janos a pesar de considerarse una población periférica y en declive.

MHC-DRB Exon 2 Diversity of the Jamaican Fruit-Eating Bat (Artibeus jamaicensis) from Mexico

Major Histocompatibility Complex (MHC) encodes a group of closely linked genes that play a central role in the vertebrate immune system, those are crucial for understanding the influence of natural selection on genetic diversity in wild populations. We examined genetic variation at the MHC class II DRB gene in 15 sampled localities of the Jamaican fruit-eating bat (Artibeus jamaicensis) in Mexico. Artibeus jamaicensis is one of the most abundant and widely distributed species in the Neotropics, and is therefore an excellent species in which to examine immunological gene variation. Using PCR amplifications, cloning and sequencing, we assessed individual DRB allelic diversity. Sequences from 193 individuals were analyzed and no deletions or insertions were detected, thus likely representing functional alleles. We identified 161 alleles (allele diversity = 0.9789 + 0.0022), with three to five alleles per individual, suggesting gene duplication events. Our results suggest the presence of recombination involved with generating DRB diversity in A. jamaicensis; we detected one recombination breakpoint and one recombination event. In the antigen-binding site (ABS), the average number of nonsynonymous substitutions per site is greater than the synonymous substitutions per site (0.7033 versus 0.2966, respectively) providing evidence for positive selection acting above the evolutionary history of the species in shaping MHC diversity.

Genetic Variation at Exon 2 of the MHC Class II DQB Locus in Blue Whale (Balaenoptera musculus) from the Gulf of California.

The genes of the Major Histocompatibility Complex (MHC) play an important role in the vertebrate immune response and are among the most polymorphic genes known in vertebrates. In some marine mammals, MHC genes have been shown to be characterized by low levels of polymorphism compared to terrestrial taxa; this reduction in variation is often explained as a result of lower pathogen pressures in marine habitats. To determine if this same reduction in variation applies to the migratory population of blue whales (Balaenoptera musculus) that occurs in the Gulf of California, we genotyped a 172 bp fragment of exon 2 of the MHC Class II DQB locus for 80 members of this population. Twenty-two putatively functional DQB allotypes were identified, all of which were homologous with DQB sequences from other cetacean species. Up to 5 putative alleles per individual were identified, suggesting that gene duplication has occurred at this locus. Rates of non-synonymous to synonymous substitutions (ω) and maximum likelihood analyses of models of nucleotide variation provided potential evidence of ongoing positive selection at this exon. Phylogenetic analyses of DQB alleles from B. musculus and 16 other species of cetaceans revealed trans-specific conservation of MHC variants, suggesting that selection has acted on this locus over prolonged periods of time. Collectively our findings reveal that immunogenic variation in blue whales is comparable to that in terrestrial mammals, thereby providing no evidence that marine taxa are subject to reduced pathogen-induced selective pressures.