Evidences of genetic bottleneck and fitness decline in <i>Luehea divaricata</i> populations from southern Brazil

Abstract

Highlights• Signatures of genetic bottlenecks and reduction of populations' fitness were observed in populations of Luehea divaricata in southern Brazil.• Lower levels of observed heterozygosity are correlated with populations' fitness, decreasing germination capacity and increasing the proportion of anomalous germinated plantlets.• Promoting the connection among populations is proposed as a key strategy towards conservation of L. divaricata genetic resources in its southernmost distribution range. AbstractExtant populations growing in regions that were refugia during the last glacial period are expected to show higher genetic diversity than populations that moved from these refugia into new areas in higher latitudes. Such new populations likely faced harsher climatic conditions, being established with reduced population size and experiencing the effects of genetic bottlenecks. In this study we employed data from nuclear SSR markers for detecting molecular signatures of genetic bottlenecks, and germination experiments to evaluate reduction of populations' fitness in natural populations of Luehea divaricata Mart. et Zucc., growing in the southern range of the species distribution (around 30°S latitude). Signatures of genetic bottlenecks and reduction of populations' fitness were observed in all populations. Lower levels of observed heterozygosity are correlated with populations' fitness, decreasing germination capacity and increasing the proportion of anomalous germinated plantlets. Promoting the connection among populations is proposed as a key strategy towards conservation of L. divaricata genetic resources in its southernmost distribution range. The offspring from crosses among populations would significantly increase the observed heterozygosity and fitness of multiple populations.

Ancient and Current Distributions of Erythrina crista-galli L. (Fabaceae) in South America

“…However, the anthropogenic climatic changes will be the main cause of extinction of species in the next 100 years, highlighting the local extinctions given by species intolerance to environmental changing factors (Cahill et al, 2012). Such event must be due to the difficulty of organisms to make physiological adjustments fast enough to adapt to the temperature increases in the time frames that should occur according to current forecasts and the fragmentation of ecosystems, in addition to numerically reducing, which impairs gene flow and reduces the genetic variability of populations (Primack & Rodrigues, 2001;Gotelli, 2007;Nagel et al, 2015) and population fitness (Stefenon et al, 2016).…”

Characterization of Plastidial and Nuclear SSR Markers for Understanding Invasion Histories and Genetic Diversity of Schinus molle L.

“…Mainly due to their locus-specific nature, co-dominance and high polymorphism, simple sequence repeats (SSR) markers have been used effectively for assessing genetic diversity, population differentiation, intra-populational genetic structure, interpopulation gene flow, and fitness of natural populations (e.g., [ 15 , 16 ]). SSR markers can be characterized in both organellar or nuclear genomes.…”

Floral morphometric analysis of Prosopis affinis Spreng. (Fabaceae) suggests flexibility of the reproductive system in isolated populations within the Brazilian Pampa

“…However, variation in these traits could occur in response to environment gradients or disturbances in abiotic or biotic conditions (Johnson & Steiner 2000, Busch 2011, Niet & Johnson 2012. Population fragmentation may decrease seed dispersal and affect the plant-pollinators interactions, disturbing fitness parameters (Aguilar et al 2006, Stefenon et al 2016 and the plant population genetic structure (Jacquemyn et al 2012, Lemos et al 2015, Nagel et al 2015.…”

“…Since the middle of the XVIII century, the Brazilian Pampa has an economy based on monoculture and livestock, exploring the grass-dominated vegetation (Roesch et al 2009). Such economic exploitation hinders the expansion of the forest formations and increases the genetic and evolutionary consequences of fragmentation in tree species within this biome (Lemos et al 2014, Nagel et al 2015, Stefenon et al 2016. Thus, considering the fragmented distribution of the Brazilian populations of P. affinis within a disturbed matrix of agricultural lands and the indirect effects of habitat fragmentation in plant breeding sys-tems, such isolated populations of this species might undergo a process of adaptation through transition from specialized to general pollination systems with mixed breeding system, giving the fact that pollinator availability might also oscillate.…”