Performance comparison of two reduced-representation based genome-wide marker-discovery strategies in a multi-taxon phylogeographic framework

Glacial history of Saxifragawahlenbergii (Saxifragaceae) in the context of refugial areas in the Western Carpathians

Despite the wealth of data available for mountain phylogeography, local-scale studies focused on narrow endemic species remain rare. Yet, knowledge of the genetic structure of such species biogeographically linked to a restricted area is of particular importance to understand the history of the local flora and its diversity patterns. Here, we aim to contribute to the phylogeographical overview of the Western Carpathians with a genetic study of Saxifragawahlenbergii, one of the most characteristic endemic species of this region. We sampled populations from all discrete parts of the species' distribution range to apply sequencing of selected non-coding cpDNA and nuclear ribosomal DNA (ITS) regions, as well as Amplified Fragment Length Polymorphism (AFLP) fingerprinting. First, while ITS sequences showed weak diversification, the genetic structure based on cpDNA sequences revealed two well-differentiated groups of haplotypes. One of them is restricted to the main center of the distribution range in the Tatra Mountains (Mts), while the second group included a series of closely related haplotypes, which in most cases were unique for particular isolated groups of populations in peripheral mountain ranges and in the south-eastern part of the Tatra Mts. AFLP fingerprinting also revealed a pattern of divergence among populations, while only partly corroborating the division observed in cpDNA. Taking into account all the data, the pattern of genetic structure, supported by the high levels of unique genetic markers in populations, may reflect the historical isolation of populations in several local refugia during the last glacial period. Not only the center of the range in the Tatra Mts, but also other, neighboring massifs (Malá Fatra, Nízke Tatry, Chočské vrchy, Muránska planina), where populations are characterized by separate plastid DNA haplotypes, could have acted as separate refugia.

Applying molecular and genetic methods to trees and their fungal communities

Forests provide invaluable economic, ecological, and social services. At the same time, they are exposed to several threats, such as fragmentation, changing climatic conditions, or increasingly destructive pests and pathogens. Trees, the inherent species of forests, cannot be viewed as isolated organisms. Manifold (micro)organisms are associated with trees playing a pivotal role in forest ecosystems. Of these organisms, fungi may have the greatest impact on the life of trees. A multitude of molecular and genetic methods are now available to investigate tree species and their associated organisms. Due to their smaller genome sizes compared to tree species, whole genomes of different fungi are routinely compared. Such studies have only recently started in forest tree species. Here, we summarize the application of molecular and genetic methods in forest conservation genetics, tree breeding, and association genetics as well as for the investigation of fungal communities and their interrelated ecological functions. These techniques provide valuable insights into the molecular basis of adaptive traits, the impacts of forest management, and changing environmental conditions on tree species and fungal communities and can enhance tree-breeding cycles due to reduced time for field testing. It becomes clear that there are multifaceted interactions among microbial species as well as between these organisms and trees. We demonstrate the versatility of the different approaches based on case studies on trees and fungi. KEY POINTS: • Current knowledge of genetic methods applied to forest trees and associated fungi. • Genomic methods are essential in conservation, breeding, management, and research. • Important role of phytobiomes for trees and their ecosystems.

Performance comparison of gel and capillary electrophoresis-based microsatellite genotyping strategies in a population research and kinship testing framework

OBJECTIVE

The advancement of molecular techniques in an era in which high-throughput sequencing has revolutionized biology renders old-fashioned alternatives to high-throughput methods obsolete. Such advanced molecular techniques, however, are not yet accessible to economically disadvantaged region-based laboratories that still obtain DNA profiles using gel-based techniques. To explore whether cost-efficient techniques can produce results that are as robust as those obtained using high-throughput methods, we compared the performance of polyacrylamide gel electrophoresis (PAGE)- and capillary electrophoresis (CE)-derived genomic data in estimating genetic diversity and inferring relatedness using 70 individuals of fine flounder (Paralichthys adspersus) selected from a hatchery population and genotyped for five microsatellite loci.

RESULTS

Here, we show that PAGE- and CE-derived genomic datasets yield comparable genetic diversity levels regarding allelic diversity measures and heterozygosity. However, relatedness inferred from each dataset showed that the categorization of dyads in the different relationship categories strongly differed. This suggests that while scientists can reliably use PAGE-derived genomic data to estimate genetic diversity, they cannot use the same for parentage testing. The findings could help laboratories committed to population research not be discouraged from using the PAGE system if high-throughput technologies are unavailable and the method is adequate to address the biological question.