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Long-distance drifting of seaweeds driven by ocean currents is an ideal model for exploring population-level genetic connectivity and phylogeographic structure. In the Indo-Pacific convergence region, we integrated phylogeographic and ocean current data and Lagrangian particle simulations to explore how the ocean currents contributed to the biogeographical patterns and population genetic connectivity of Sargassum polycystum. The oceanographic transport and direction of gene flow was in line with contemporary ocean currents. The S. polycystum geographical dispersal from glacial refugia homogenized the footprint of genetic divergence. The multidisciplinary intersection provides insights into the evolutionary history and biogeographic conservation of tropical seaweeds in the Indo-Pacific convergence region.

The evolutionary processes underlying the high diversity and endemism in the Cerrado, the most extensive Neotropical savanna, remain unclear, including the factors promoting the presence and evolution of savanna enclaves in the Amazon forest. In this study, we investigated the effects of past climate changes on genetic diversity, dynamics of species range and the historical connections between the savanna enclaves and Cerrado core for Qualea grandiflora, a tree species widely distributed in the biome. Totally, 40 populations distributed in the Cerrado core and Amazon savannas were analyzed using chloroplast and nuclear DNA sequences. We used phylogeographic, coalescent and ecological niche modeling approaches. Genetic data revealed a phylogeographic structure shaped by Pleistocene climatic oscillations. An eastern-western split in the Cerrado core was observed. The central portion of the Cerrado core harbored most of the sampled diversity for cpDNA. Ecological niche models predicted the presence of a large historical refuge in this region and multiple small refuges in peripheral areas. Relaxed Random Walk (RRW) models indicated the ancestral population in the north-western border of the central portion of the Cerrado core and cyclical dynamics of colonization related to Pleistocene climatic oscillations. Central and western ancient connections between Cerrado core and Amazonian savannas were observed. No evidence of connections among the Amazonian savannas was detected. Our study highlights the importance of Pleistocene climatic oscillations for structuring the genetic diversity of Q. grandiflora and complex evolutionary history of ecotonal areas in the Cerrado. Our results do not support the recent replacement of a large area in the Amazon forest by savanna vegetation. The Amazonian savannas appear to be fragmented and isolated from each other, evolving independently a long ago.

The evolutionary processes underlying the high diversity and endemism in the Cerrado, the most extensive Neotropical savanna, remain unclear, including the factors promoting the presence and evolution of savanna enclaves in the Amazon forest. In this study, we investigated the effects of past climate changes on genetic diversity, dynamics of species range and the historical connections between the savanna enclaves and Cerrado core for Qualea grandiflora, a tree species widely distributed in the biome. Totally, 40 populations distributed in the Cerrado core and Amazon savannas were analyzed using chloroplast and nuclear DNA sequences. We used phylogeographic, coalescent and ecological niche modeling approaches. Genetic data revealed a phylogeographic structure shaped by Pleistocene climatic oscillations. An eastern-western split in the Cerrado core was observed. The central portion of the Cerrado core harbored most of the sampled diversity for cpDNA. Ecological niche models predicted the presence of a large historical refuge in this region and multiple small refuges in peripheral areas. Relaxed Random Walk (RRW) models indicated the ancestral population in the north-western border of the central portion of the Cerrado core and cyclical dynamics of colonization related to Pleistocene climatic oscillations. Central and western ancient connections between Cerrado core and Amazonian savannas were observed. No evidence of connections among the Amazonian savannas was detected. Our study highlights the importance of Pleistocene climatic oscillations for structuring the genetic diversity of Q. grandiflora and complex evolutionary history of ecotonal areas in the Cerrado. Our results do not support the recent replacement of a large area in the Amazon forest by savanna vegetation. The Amazonian savannas appear to be fragmented and isolated from each other, evolving independently a long ago. [ABSTRACT FROM AUTHOR]

Intensive malacological surveys coupled with environmental DNA analyses in France has led to the discovery of new populations of the quagga mussel Dreissena rostriformis bugensis (Andrusov, 1897), an introduced and invasive freshwater bivalve species. Molecular analyses confirmed the identification of the species based on a barcoding approach using both CO1 and 16S genes fragments. Discovered in 2011 in the rivers of north-east France, the quagga Mussel has now colonized the Rhône drainage. This advance represents not only the colonization of a new coastal drainage (the Rhône Rivers flows to the Mediterranean side of France), but also a spectacular 400-km leap south of its previously known range. Further expansion routes provided by canals between main coastal drainages are discussed. For the first time, we propose to use environmental DNA to assess absence, thus paving the way for future freshwater invasive species monitoring methods.

The article presents a study on the diversity pattern of Swiss stone pine, Pinus cembra L. along the Carpathian range. The range characteristics of nine Swiss stone pine populations were analyzed using six chloroplast DNA microsatellites (cpSSR). The study revealed that the most diverse populations can be found in the Retezat Mountains in South Carpathians and the High Tatras, while the diversity of population decreases towards Eastern Carpathian.

Numerous studies of variation in mtDNA in Amerindian populations established that four haplogroups are present throughout both North and South America. These four haplogroups (A, B, C, and D) and perhaps a fifth (X) in North America are postulated to be present in the initial founding migration to the Americas. Furthermore, studies of ancient mtDNA in North America suggested long-term regional continuity of the frequencies of these founding haplogroups. Present-day tribal groups possess high frequencies of private mtDNA haplotypes (variants within the major haplogroups), consistent with early establishment of local isolation of regional populations. Clearly these patterns have implications for the mode of colonization of the hemisphere. Recently, the earlier consensus among archaeologists for an initial colonization by Clovis hunters arriving through an ice-free corridor and expanding in a "blitzkrieg" wave was shown to be inconsistent with extensive genetic variability in Native Americans; a coastal migration route avoids this problem. The present paper demonstrates through a computer simulation model how colonization along coasts and rivers could have rapidly spread the founding lineages widely through North America. [ABSTRACT FROM AUTHOR]