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The northern quahog, Mercenaria mercenaria (= hard clam) is an important aquaculture species on the U.S. east coast and shares a partially sympatric distribution with a sister species Mercenaria campechiensis which is endemic to the mid-Atlantic coast from the Chesapeake Bay to Florida and the Gulf of Mexico. These two species are morphologically similar, and their identification is laborious and challenging. To support aquaculture breeding and restoration activities, it is essential to develop an accurate and easy method to identify the two Mercenaria species. In the present study, high-melting resolution analysis was applied to identify these two Mercenaria species and their hybrids using three genes of cytochrome oxidase subunit 1 (COJ), mitochondrial large ribosomal subunit (I6S r RNA), and internal transcribed spacer 1 (ITSI). The temperature melting points (TJ of COl, 16S rRNA, and ITSI were significantly different between the two Mercenaria species and could be used to distinguish M. mercenaria and M. campechiensis. By use of the melting T of COl, 16S r RNA, and ITSI, a discriminant function equation was established to effectively eliminate the impacts of intraspecific sequence variations on species identification. Compared with their true species classification, the accuracy of the predicted classification of each sample was 100% based on the discriminant function equation. Furthermore, a linear discriminant analysis model was used for cross-validation and the mean classification success was 100% with no observed erroneous classification. Moreover, the interspecific hybrids of M. mercenaria and M. campechiensis were verified by the melting curve of nuclear DNA marker ITSI, and their maternity was further clarified by mitochondrial DNA markers COl and 16S rRNA. The methodology developed in this study would be useful as a rapid and accurate tool to support Mercenaria aquaculture, breeding, and restoration. KEY WORDS: high-resolution melt analysis, Mercenaria mercenaria, Mercenaria campechiensis, species identification, hybrid, discriminant analysis, INTRODUCTION The northern quahog, Mercenaria mercenaria (also named hard clam) is an intertidal benthic infaunal species along the western Atlantic coast from the Gulf of St. Lawrence to Florida (Harte [...]

Byline: H. Meydan, F. S. Rashaydeh, R. M. Al-Atiyat and B. I. Yildiz Key words: Genetic diversity, Awassi Sheep, Fertile Crescent, Genetic Markers. INTRODUCTION Livestock, in diversified farming systems, perform [...]

While most population genetic studies focus on breeding populations, patterns of genetic structuring of migrating birds can provide similar insights of species distribution, yet population structuring is rarely studied at migratory stopover sites. Philopatric species such as the Eastern Phoebe (Sayornis phoebe) return to the same breeding sites, which reduces gene flow between breeding populations and leads to population structuring. Therefore, we should be able to detect population differentiation at migratory stopover sites if genetically distinct breeding populations converge during migration. Our objective was to determine if we could detect population structuring among migrating Eastern Phoebes of unknown origin. Panola Mountain State Park (PANO) is a restored grassland in central Georgia where phoebes are consistently captured throughout the annual cycle. We collected blood samples from 73 individuals at PANO between November 2017 and January 2019 and amplified 12 highly variable microsatellite loci specific to phoebes. Since the phoebes were of unknown origin captured at the same site, we assigned a priori populations based on (1) season of capture and (2) date of capture. Our [F.sub.ST] results revealed that phoebes captured during the breeding season are genetically different compared to those captured during fall. These genetic differences are either a result of genetic differences between migratory individuals (fall and wintering seasons) and resident breeding populations (breeding season) or genetically distinct breeding populations that use PANO as a migratory site at different times. While understanding which of these is responsible for our results requires additional study, this study is the first to show population structuring of a migratory species using genetic markers at a migratory stopover site when distinct breeding grounds and populations are otherwise unknown. Received I July 2020. Accepted I October 2021. Key words: genetic structure, migration ecology, migratory birds, population genetics. Micntras que la mayoria de los estudios geneticos sc enfocan en poblaciones reproductivas. los patrones de estrucuira genetica de aves migratorias pueden proporcionar aportes similares a la distrihucion de las especies. si bien la estructura de las poblaciones es raramente estudiada en sitios de parada migratoria. Las especies con filopatria coino el mosquero Sayornis phoebe rcgresan a los mismos sitios de reproduccion, lo cual reduce cl fiujo genico cntre poblaciones reproductivas y rcsulta en poblaciones estructuradas. Por ello. debcriamos poder detectar diferencias poblationales en sitios de parada migratoria si las poblaciones geneticamente diferenciadas convergen durante la migration. Nuestro objetivo fue determinar si podriamos detectar estructura poblacional entre mosqueros de diferente origen. HI Panola Mountain State Park (PANO) es una pradera restaurada en el centre de Georgia donde los mosqueros son consistentemente capturados a lo largo del ciclo anual. Colectamos mucstras de sangre de 73 individuos en PANO entre novicmbre de 2017 y enero de 2019, y ampliticamos 12 loci altamcnte variables especificos a los mosqueros. Dado que los mosqueros cran de origenes desconocidos y capturados en el rnismo sitio, les asignamos poblaciones a priori con base en (I) temporada de captura y (2) fecha de captura. Nucstros resultados de f'sr revelaron que los mosqueros capturados durante la temporada reproductiva son geneticamente diterentes a los capturados durante el otono. Estas son resultado dc diferencias gencticas entre individuos migratorios (temporadas de otono e invernal) y poblaciones residentes reproductivas (temporada reproductiva) o de poblaciones reproductivas geneticamente distintas que usan PANO como sitio migratorio en diferentes periodos. Si bien entender cual de estas razones es responsable por nuestros resultados requiere estudios adicionales, esta investigation es la primera que muestra la estructura de poblaciones de una especie migratoria usando marcadores geneticos en su sitio de parada migratoria cuando las areas de reproduccion y las poblaciones son desconocidas. Palabras clave: aves migratorias, ecologia de la migration, estructura genetica. genetica de poblaciones., Gene flow is a result of bird movements with successful reproduction across breeding ranges, which increases genetic similarity among breeding populations (Ramos et al. 2016). Conversely, populations become genetically differentiated [...]