Conectividad genética de Stegastes acapulcoensis (Pomacentridae) en el Pacífico central de México

The family Pomacentridae includes fish species that are abundant on coral reef systems, like the ones included on Stegastes genus with organisms that in adult stage are herbivore, territorial and dependent of a substrate for reproduction. We analyzed the genetic connectivity of Stegastes acapulcoensis between sites of the Mexican Pacific, separated for a maximum geographic distance of 435 km. We assess the genetic differentiation between four sites with four microsatellite loci and traditional estimative methods, having as a result values of FST = 0.0017 (p < 0.01) and RST = 0.0279 (p < 0.01). Equally, with DEST and Bayesian methods null or little genetic differentiation between sites was detected. These results are explained considering the dispersal ability of S. acapulcoensis on its pelagic larval stage, which follows the Mexican West Current pattern. Finally, due our results we suggest that it is possible to infer that other demersal fish species may present the same connectivity pattern. The present work constitutes the first evidence that suggests the necessity to join seven priority marine areas of Mexico into a unique continual area.La familia Pomacentridae incluye especies de peces que son abundantes en los sistemas arrecifales, como las incluidas en el género Stegastes, con representantes que en etapa adulta son herbívoros, territoriales y dependientes de un substrato para su reproducción. En este estudio se analizó la conectividad genética de Stegastes acapulcoensis entre cuatro poblaciones del Pacífico mexicano, separadas por una distancia geográfica máxima de 435 km. Se estudió la diferenciación genética entre cuatro localidades, con cuatro loci de microsatélites y estimadores tradicionales, obteniendo valores de FST = 0.0017 (p < 0.01) y de RST = 0.0279 (p < 0.01). De igual manera con DEST y métodos bayesianos, se detectó escasa o nula diferenciación genética entre las localidades estudiadas. Los resultados pueden explicarse debido a la dispersión de S. acapulcoensis en su etapa de larva pelágica, ya que dichas larvas pueden seguir los cambios estacionales de dirección de la Corriente del Oeste de México. Finalmente a través de los resultados de conectividad obtenidos para Stegastes acapulcoensis se infiere que otras especies de peces demersales podrían presentar el mismo patrón de conectividad, por lo que este estudio es también la primera evidencia para sugerir la necesidad de unir siete áreas marinas prioritarias para la conservación de México

Caracterización de sistemas de producción del guajolote (Meleagris gallopavo gallopavo) de traspatio en las regiones fisiográficas del estado de Michoacán, México

En este trabajo se caracterizaron unidades de producción (UP) de traspatio de guajolote doméstico en las cinco regiones fisiográficas del estado de Michoacán. La meleagricultura de traspatio se lleva a cabo en todas las regiones fisiográficas del estado, con UP promedio de 7.20 a 14.80 aves. La relación hembra/macho es de 1.69 a 3.69 hembras por macho. De acuerdo a la coloración del plumaje, se encontraron las variedades Bronceado, Narrangansett, Palma Real, Negro español, Slate o plateado y Buffy (café o rojo) y otros colores que no se pudieron asignar a las variedades descritas. El peso en adultos mayores de 12 meses fue de 6.70 a 8.90 kg machos y 2.90 a 4.35 kg hembras. Las aves más pesadas se localizaron en las regiones de clima templado. Las hembras anidan 2 a 3 veces por año, produciendo de 12 a 15 huevos por evento con nacimientos de 10 a 12 pavipollos por evento. El 94.3 % de las unidades son no tecnificadas, con incorporación de algunas prácticas de manejo mejorado, como utilización de alimento balanceado en pavipollos hasta los dos meses de edad, poco o nulo esquema de vacunación y sin utilización de variedades "mejoradas", lo que indica que el tipo genético de guajolote es autóctono y es un fondo genético propio

Assessing genetic structuring for endangered Chelonia mydas (Testudines: Cheloniidae) in southwest Cuba using microsatellites.

Understanding the population genetic structure of the species is essential for determining the possible management units (UM) and their conservation and/or sustainable exploitation with it. Chelonia mydas is recognized as an endangered philopatric turtle. This work aims to describe the population structure of the green turtle in southwestern Cuba through traditional analytical approaches and allocation methods. The collections were made between 1998 and 2007 on five beaches in the Cuban southwest. Seven microsatellite loci from 149 individuals were amplified and genetic variability parameters were calculated. The population structure was inferred through the use of Wright's F, Analysis of Molecular Variance (AMOVA), and population assignment algorithms based on Bayesian analysis (STRUCTURE) and factorization of sparse non-negative matrices (implemented in R). Most of the loci were not in Hardy-Weinberg equilibrium, and several presented linkage disequilibrium. The AMOVA and differentiation statistics suggest the presence of structure at the geographical level analyzed. The highest value of ΔK and the lowest value of cross-entropy were reached for K = 2, a result that suggests that in southwestern Cuba there is the contribution of two ancestral populations of Chelonia mydas. Relative migration estimates indicate active genetic exchange between nesting colonies in southwestern Cuba.Este estudio ha recibido fondos del programa de Doctorado UNAM-UH y TWAS. We thank the protected areas administration, and the forest rangers protecting and monitoring the sea turtle nesting areas; the Ministry of Science, Technology, and Environment for the authorization to access natural areas and for their support of the monitoring work; to all workers and volunteers for their effort to protect sea turtles in Cuba. We also thank Laboratorio de Genética of Unidad Académica Mazatlán, Instituto de Ciencias del Mar y Limnología UNAM and Centro de Investigaciones en Ecosistemas in UNAM, Morelia, for facilities and equipment used in our genetic analyses

Assessing genetic structuring for endangered "Chelonia mydas" (Testudines: Cheloniidae) in southwest Cuba using microsatellites

Understanding the population genetic structure of the species is essential for determining the possible management units (UM) and their conservation and/or sustainable exploitation with it. Chelonia mydas is recognized as an endangered philopatric turtle. This work aims to describe the population structure of the green turtle in southwestern Cuba through traditional analytical approaches and allocation methods. The collections were made between 1998 and 2007 on five beaches in the Cuban southwest. Seven microsatellite loci from 149 individuals were amplified and genetic variability parameters were calculated. The population structure was inferred through the use of Wright's F, Analysis of Molecular Variance (AMOVA), and population assignment algorithms based on Bayesian analysis (STRUCTURE) and factorization of sparse non-negative matrices (implemented in R). Most of the loci were not in Hardy-Weinberg equilibrium, and several presented linkage disequilibrium. The AMOVA and differentiation statistics suggest the presence of structure at the geographical level analyzed. The highest value of ΔK and the lowest value of cross-entropy were reached for K = 2, a result that suggests that in southwestern Cuba there is the contribution of two ancestral populations of Chelonia mydas. Relative migration estimates indicate active genetic exchange between nesting colonies in southwestern Cuba.   Received: 07.02.2022 Accepted: 09.12.2022 Editor: Erik García-Machad

Detecting patterns of fertilization and frequency of multiple paternity in Chelonia mydas of Colola (Michoacán, Mexico)

We present a microsatellite analysis that allows an indirect determination of the process of fertilization in the genital tract of Chelonia mydas. The strategy was based in that the order of oviposition is related to fertilization order. Once the genotype of the offspring was obtained through microsatellite analyses, it was possible to determine the frequency of multiple paternity and to infer the presence of anatomical structures or physiological mechanisms that allow females to undergo cryptic choice processes, which allowed us to hypothesize the existence of post-copula factors that determine reproductive success in a polyandrous system. This paper does not show the presence of physiological mechanisms that allow control of fertilization order in polyandrous females of Chelonia mydas

Caracterización molecular de aislamientos de Staphylococcus spp. asociados a mastitis bovina en Tarímbaro, Michoacán

Mastitis is a disease of dairy cattle worldwide that causes decreased milk quality/yield, resulting in major economic losses. Mastitis is caused by a wide variety of organisms, including Staphylococcus aureus as a major pathogen. The purpose of this research was to characterize 20 Staphylococcus spp. isolates from the mammary gland of mastitic, lactating, backyard cattle, using both the Random Amplified Polymorphic DNA (RAPD) analysis, and sensitivity tests to 13 antibiotics and 1 detergent. Sensitivity tests to 13 antibiotics showed that all isolates were resistant to penicillin but sensitive to cephalothin, erythromycin, and trimethoprim. All isolates were susceptible to a 90% similarity in the RAPD band pattern, while isolates SA35 & SA36 were identical to each other. Nevertheless, all other isolates showed different amplification profiles. Isolates SA7 & SA8, SA30 & SA32, SA35 & SA36 had similar antibiotic resistance/RAPD patterns, suggesting re-isolation. Staphylococcus isolates collected in Tarímbaro, Michoacán showed several different amplification patterns.La mastitis es una enfermedad que afecta al ganado bovino lechero a nivel mundial, provocando una disminución en la calidad y cantidad de la leche producida, lo cual genera pérdidas económicas considerables. Esta enfermedad es causada por una variedad de microorganismos, entre los cuales Staphyloccocus aureus es uno de los más importantes. El objetivo del trabajo fue caracterizar 20 aislamientos de Staphylococcus spp. obtenidos de la glándula mamaria de vacas lactantes con mastitis en un sistema de producción de traspatio, mediante el uso de polimorfismos derivados de la amplificación al azar de ADN (RAPD's) y su sensibilidad hacia trece antibióticos y 1 detergente. Las pruebas de sensibilidad a los 13 antibióticos demostraron que todos los aislamientos fueron resistentes a penicilina y sensibles a cefalotina, eritromicina y trimetoprim. Todos los aislamientos fueron susceptibles a una concentración menor de 6 µg/ml de bromuro de cetil trimetil amonio (CTAB). La caracterización molecular permitió determinar que los aislamientos SA7 y SA8, SA30 y SA32, presentaron una similitud superior al 90 % en el patrón de bandas obtenida por RAPD, mientras que los aislamientos SA35 y SA36 fueron idénticos, sin embargo, el resto de los aislamientos presentaron perfiles de amplificación distintos. Los aislamientos SA7 y SA8, SA30 y SA32, SA35 y SA36, tuvieron patrones de resistencia a antibióticos y de RAPD similares, por lo que probablemente se trató de reaislamientos. Los aislamientos de Staphylococcus de Tarí­mbaro, Michoacán presentaron una diversidad de perfiles de amplificación

Diversidad genética y estructura de poblaciones de pavos domésticos mexicanos

En este estudio se analizaron niveles de diversidad y estructura genética de 144 guajolotes domesticados de poblaciones de traspatio de las cinco regiones fisiográficas de Michoacán y 16 guajolotes de dos poblaciones silvestres del centro de México utilizados como grupo externo de referencia, mediante siete loci de microsatélites. En guajolotes domesticados el promedio de heterocigosidad fue moderado (0.535 ± 0.285) comparado con silvestres (0.701 ± 0.068). Los guajolotes domesticados mostraron diferenciación entre poblaciones (FST= 0.122) a través de los loci. Los porcentajes de diferenciación estimados por Análisis de Varianza Molecular fueron bajos entre poblaciones (14 % domesticados y 6 % silvestres) y altos dentro de las poblaciones (86 % domesticados y 94 % silvestres). Los análisis de similitud mostraron la formación de un grupo con guajolotes silvestres y dos grupos basales con domesticados; un grupo basal incluyó tres subgrupos con poblaciones de las regiones Bajío, Faja Volcánica Transversal y Balsas, y un segundo grupo basal incluyó dos subgrupos con poblaciones de las regiones Sierra y Costa. El análisis de estructura genética mostró tres grupos para guajolotes domesticados y uno para silvestres. Una prueba de Mantel mostró aislamiento por patrón de distancia (r=0.84, P<0.05) entre poblaciones domesticadas. Los grupos genéticos de guajolotes domesticados fueron congruentes con los datos morfométricos previamente obtenidos de la misma población; un grupo correspondió a poblaciones de Bajío y Balsas (morfometría intermedia), el segundo grupo incluyó a la población de Faja Volcánica Transmexicana (grandes y pesados), y el tercer grupo correspondió a poblaciones de Sierra y Costa (ligeros y pequeños)

Reproductive benefits and reduced investment in parental care behavior associated with reproductive groups of males in Abudefduf troschelii

Fishes of the family Pomacentridae present a wide diversity of mating systems, ranging from polygyny to promiscuity and from individual territorial defense to the establishment of reproductive colonies of males. The damselfish species Abudefduf troschelii has a reproductive colony mating system, in which males temporarily aggregate in reproductive areas to court and attract females. Males defend an individual territory where they receive eggs and perform paternal care behaviors for their offspring. The present study evaluated the advantages of the colonial mating system in A. troschelii. During an entire reproductive period, in a breeding colony within a rocky reef, we located, marked, geo-referenced, and measured the distances between the territories of all males. We quantified the variance among males in their patterns of paternal care investment, eggs acquired, hatching success, reproductive success, body size, and changes in body coloration. We found that males spatially distributed their nests in groups or independently (i.e., solitary nests). Nesting groups are formed by larger males that show intense nuptial coloration during the entire receptivity period. They are located centrally to the colony and consist of three to six males whose territories overlap. In contrast, small solitary males that fail to acquire or maintain nuptial coloration during the receptivity period establish their nests peripherally to the colony, away from the territories of other males. Our results highlight that the reproductive benefits of colonial nesting are unequal for males, as the spatial distribution of nests within the colony determines the reproductive success of males. Group nesting confers the highest reproductive benefits to males regarding eggs obtained, hatching success, and relative fitness and also enables males to reduce their parental investment in brood care behaviors. The preference of females for oviposition could be associated with greater intrasexual competitiveness, defense ability, body condition, or experience of group-nesting males located at the center of the colony or because their progeny will have a lower probability of predation than they would in solitary nests males

Phylogeography of the purple snail Plicopurpura pansa along the Mexican Pacific coast

The purple snail Plicopurpura pansa is a common member of the rocky intertidal community of the Tropical Eastern Pacific. It has a free-living larva that is dispersed by marine currents. We analyzed the demographic (historic), genetic, and phylogeographic structure of P. pansa using a fragment of the cytochrome b gene (687 bp). Data were analyzed by analysis of molecular variance, nested clade analysis (NCA), and a mismatch distribution analysis under the expanding population hypothesis. A total of 219 organisms were collected from 16 localities along the Mexican Pacific coast and one in Costa Rica. We obtained a total of 92 haplotypes. Genetic differences among Mexican populations were low. The Clarión Island population was significantly different from 6 of the Mexican populations studied. This result was attributed to the fact that Clarión is an oceanic island and the currents veer offshore most of the year. Haplotype network and mismatch distribution analyses indicated that the Mexican populations are undergoing expansion. The NCA confirmed a contiguous range expansion of haplotypes and this result may be related to the time that larvae spend in marine currents and to the effect of natural barriers, such as gyres, in Central America and the Isthmus of Tehuantepec.