With the increasing affordability of next-generation sequencing technologies, genotype-by-sequencing has become a cost-effective tool for ecologists and conservation biologists to describe a species' evolutionary history. For host–parasite interactions, genotype-by-sequencing can allow the simultaneous examination of host and parasite genomes and can yield insight into co-evolutionary processes. The eastern oyster, Crassostrea virginica, is among the most important aquacultured species in the United States. Natural and farmed oyster populations can be heavily impacted by ‘dermo’ disease caused by an alveolate protist, Perkinsus marinus. Here, we used restricted site-associated DNA sequencing (RADseq) to simultaneously examine spatial population genetic structure of host and parasite. We analysed 393 single-nucleotide polymorphisms (SNPs) for P. marinus and 52,100 SNPs for C. virginica from 36 individual oysters from the Gulf of Mexico (GOM) and mid-Atlantic coastline. All analyses revealed statistically significant genetic differentiation between the GOM and mid-Atlantic coast populations for both C. virginica and P. marinus, and genetic divergence between Chesapeake Bay and the outer coast of Virginia for C. virginica, but not for P. marinus. A co-phylogenetic analysis confirmed significant coupled evolutionary change between host and parasite across large spatial scales. The strong genetic divergence between marine basins raises the possibility that oysters from either basin would not be well adapted to parasite genotypes and phenotypes from the other, which would argue for caution with regard to both oyster and parasite transfers between the Atlantic and GOM regions. More broadly, our results demonstrate the potential of RADseq to describe spatial patterns of genetic divergence consistent with coupled evolution.

Gerbera is an important commercial flower crop in the world. Augmenting the genetic diversity is desirable for further improvement in Gerbera breeding programme. Thirty-seven (37) Gerbera accessions were evaluated and analysed for genetic variability, heritability, correlation and path coefficient analysis using yield and quality traits. Results showed that phenotypic coefficients were higher than genotypic coefficients of variation for all the characters. All the traits, except stalk and flower diameter, had high heritability (>60%) and genetic advance (>20%). Based on cluster analysis, the 37 accessions were grouped into seven clusters. Cluster I consists of the maximum number of genotypes (22), while clusters IV–VII are monogenotypic with unique traits. Cluster analysis (D2) showed wider genetic diversity within and between the clusters. The first four principal components (Eigenvalue >1) contributed 72.3% of the total variation. The number of leaves, number of flowers and flower stalk length contributed the most to genetic divergence. Flower yield showed a significant positive genotypic correlation with the number of leaves and suckers. The path analysis (genotypic) revealed that number of suckers, flower stalk diameter and flower stalk length contribute major positive direct effects on number of flowers. Therefore, the wide genetic variability existing in the germplasm may facilitate improvement in gerbera crops. Superior lines (RCGH-12, -22, -114, -117) with higher yield (>23 flowers/plant) and vase life (>5 days) could be promoted for commercial production under open field conditions. While RCGH 28 has a dwarf flower stalk that can be promoted for pots and decoration purposes.

El estudio del parentesco permite comprender mejor las sociedades antiguas porque está relacionado con el comportamiento social, económico, político y reproductivo de la población. Es posible conocer la magnitud de la endogamia y hacer inferencias sobre la movilidad de ambos sexos. Una mayor similitud genética promedio dentro de muestras femeninas sugiere mayor migración masculina (modelo de residencia posmarital matrilocal). A la inversa se deduce un modelo de residencia patrilocal y si no hay diferencias se infiere un modelo bilocal. Nuestro objetivo es conocer la divergencia genética entre grupos incas del altiplano del noroeste de Cusco utilizando caracteres cuantitativos del cráneo para estimar el parentesco, el número de migrantes por generación y el patrón de residencia posmarital. Los restos óseos empleados (99 cráneos masculinos y 75 femeninos) proviene de los sitios Paucarcancha, Patallacta y Torontoy. Se aplicaron técnicas de análisis multivariado y modelos derivados de la genética de poblaciones. Existen diferencias morfológicas entre los sitios a pesar de la escasa distancia geográfica. La divergencia genética fue de 0,035 (siete individuos migrantes por generación). La varianza dentro de grupos es similar en ambos sexos (modelo posmarital bilocal). Se discute la evidencia obtenida con otras localidades y subregiones del Área Andina Centro Meridional.

The current study focused on characterization of the underlying genetic divergence in inbred lines developed from local landraces of North Eastern Hill Region of India – a designated Asiatic maize diversity centre – following six generations of inbreeding. Substantial genetic differentiation was indicated based on very high to moderate Fst values for 22 of the 38 simple sequence repeat markers studied. STRUCTURE analysis partitioned the subset into two distinct and one admixture subgroup (Populations I, II and III respectively) accompanied by a significant reduction in heterozygosity. Population II was further subdivided into subpopulations Pop-M9 and Pop-T9. Nei's pairwise genetic distance and population Fst values indicated that Populations I and II were more divergent with neighbour joining clustering analysis clearly defining landraces originating from the states of Tripura (Population II) and Sikkim (Population I) as most divergent. Principal coordinates analysis could explain 31.26% of the variation present in the subgroups wherein Population I was more variable. Analysis of molecular variance and Fst coefficients (P < 0.001) indicated 17% population structuring with 55% variation detected for individuals within populations. These results combined with the presence of phenotypic variability in the subgroups for yield traits supported by results of a preliminary partial diallel analysis strongly suggest the existence of distinct heterotic groups. Divergence studies are crucial for exploiting heterosis, and the current study would go a long way to help establish a germplasm base for developing varieties with improved agronomic performance and surer commercial prospects no reports of which are available thus far.

En las sociedades andinas actuales las relaciones de parentesco determinan el tipo de matrimonio y el patrón de residencia posmarital que garantizan el manejo de los recursos, la supervivencia y la estabilidad reproductiva de la población. Sin embargo, es escasa la información disponible en el Área Andina Centro-Sur (AACS) para explicar los sistemas de parentesco durante el poblamiento original del territorio y su impacto en la estructura de las poblaciones locales posteriores a la conquista y colonización europea. En el presente trabajo se investiga el patrón residencial en dos sectores del AACS a partir de datos bioarqueológicos disponibles para el Noroeste Argentino y Norte de Chile. La información necesaria pudo ser recuperada a partir de la arqueología y de la antropología física regional. La muestra proviene de 8 localidades y 44 sitios con fechados que cubren el intervalo cronológico desde 3000 aC hasta 1450 dC, desde grupos arcaicos tempranos hasta comunidades agroalfareras tardías. Se emplearon 1.897 observaciones y 27 variables craneométricas. El análisis se realizó con técnicas estadísticas multivariadas: el cálculo de la varianza generalizada (determinante de la matriz de varianzas y covarianzas) para cada sexo y la estimación de los estadísticos de distancia (D2) y divergencia fenotípica (Fst) entre grupos y sexos. Los resultados revelan el efecto de distintos flujos migratorios que determinaron la estructura de las poblaciones. En todos los casos la varianza generalizada masculina es mayor que la femenina indicando una mayor variabilidad entre sitios y una mayor actividad migratoria. Los valores de D2 y Fst femeninos son mayores entre regiones y localidades con una menor tasa migratoria. Estos resultados indican, en general, la prevalencia de una estrategia de supervivencia basada en un sistema de parentesco que favoreció un modelo de residencia matrilocal.

In order to confirm the genetic relationship between the Yellow Sea and East China Sea populations of mantis shrimps Oratosquilla oratoria, fragments of mitochondrial DNA COI gene samples were analysed. A total of 212 individuals from nine localities in the East China Sea and Yellow Sea were collected and 108 haplotypes were detected. Neighbour-joining analysis revealed a complete genetic break between the Yellow Sea and East China Sea, which was consistent with the previous mtDNA 16S rRNA. Pleistocene isolation and the current physical barrier were responsible for the complete genetic break between the East China Sea and Yellow Sea. Furthermore, local adaptation in the COI gene may also be contributed to by the genetic differentiation between the populations of the Yellow Sea and East China. The different Ka/Ks ratios between the two clades may reflect different selection pressures and local adaptation on the fragment of COI gene.

The termite species Macrotermes bellicosus has a vast geographical distribution, which can produce genetic divergence in populations that evolve in its different environments. Experiments carried out on digestive oxidases in two populations of M. bellicosus originating from Chad and from Côte d'lvoire showed differences in the rate of their enzymatic activities. Populations from Côte d'lvoire showed significantly higher degradation activity against fresh vegetal matter than populations from Chad.