Patterns Of Phenotypic Variability Research Articles

Unlocking the Patterns of the Tunisian Durum Wheat Landraces Genetic Structure Based on Phenotypic Characterization in Relation to Farmer’s Vernacular Name

During the 1970s, Tunisian durum wheat landraces were replaced progressively by modern cultivars. These landraces are nowadays maintained by smallholder farmers in some ecological niches and are threatened gradually by extinction resulting in the narrowing of the genetic diversity. This study aims to investigate patterns of phenotypic variability using twelve quantitative traits in a panel of 189 durum wheat landraces and seven checks, based on farmer’s population name attribution and genetic structure. Our results showed high phenotypic variability among and within landraces and checks for ten out of twelve studied traits. The principal components analysis showed similar grouping using farmers name attribution and genetic structure using K = 6. These results confirmed the identification of a new gene pool in the oases of Tunisia, represented by the sub-population Jenah Zarzoura and the robustness and high relationships between phenotypic and genome-wide genetic structure using DArTseq method. These findings will enhance the conservation efforts of these landraces and their use in breeding efforts at national and international levels to adapt to dry conditions.

Scale-dependent patterns of intraspecific trait variations in two globally invasive species.

Animal species often show substantial intraspecific trait variability (ITV), yet evidence for its flexibility across multiple ecological scales remains poorly explored. Gaining this knowledge is essential to better understand the different processes maintaining ITV in nature. Due to their broad geographic ranges, widespread invasive species are expected to display strong phenotypic variations across their distribution. Here, we quantified the scale-dependent patterns of morphological variability among invasive populations of two global freshwater invaders-red swamp crayfish Procambarus clarkii and pumpkinseed sunfish Lepomis gibbosus-both established in American and European lakes. We quantified patterns in body morphology across different ecological (Individual and Population) and spatial scales (Region). We then analyzed the scale-dependency of morphological variations among lake populations that span a diversity of abiotic and biotic conditions. Next, we used stable isotope analyses to test the existence of ecomorphological patterns linking morphology and trophic niche of individuals. We found that trait variations mainly accounted for at the regional and individual levels. We showed that populations of both species strongly differed between United States and Europe whereas habitat characteristics had a relatively minor influence on morphological variations. Stable isotope analyses also revealed that ecomorphological pattern for the trophic position of L. gibbosus was region-dependent, whereas no ecomorphological patterns were observed for P. clarkii. Overall, our study strongly supports the notion that the patterns of phenotypic variability among invasive populations are likely to modulate the ecological impacts of invasive species on recipient ecosystems.

Acclimatory capacity of the Gorgonian Isis hippuris Linnaeus, 1758 to environmental change in SE Sulawesi, Indonesia

Coral reefs within the Indonesian archipelago are some of the most biodiverse yet anthropogenically compromised marine ecosystems. Within the Wakatobi Marine National Park (WMNP), SE Sulawesi, Indonesia, pronounced environmental clines are either caused or exacerbated by marine resource subsistence and destruction. The protected zooxanthellate gorgonian (sea fan coral) Isis hippuris Linnaeus, 1758 however, thrives on degraded reefs, with distinct morphotypes across contrasting reef environments within the region. To investigate if I. hippuris morphotypes are environmentally induced (plastic) or genetically derived (fixed), reciprocal transplant experiments (RTEs) were conducted across environmental gradients of light attenuation and anthropogenic disturbance. Phenotypic traits were measured and grouped into modules (colony, polyps, sclerites, optical parameters) to assess the physiological responses and endosymbiont specificity of each I. hippuris morphotype to environmental change. Trait modules were then modelled for tests of integration to determine phenotypic traits that interact to delimit I. hippuris morphotypes in response to environmental perturbation. After one-year, survivorship was lowest in clones transplanted from healthy to the degraded reef, suggesting the onset of immigrant inviability. Multivariate analyses revealed that phenotypic traits in healthy source colonies consistently showed significant trait plasticity, whereas residents from the impacted site were relatively insensitive to environmental change. Of the 38 phenotypic traits assessed, 17 were identified as driving test dissimilarities, most notably in branching dynamics, polyp density, capstan and spindle sclerite dimensions, and Symbiodinium chlorophyll a light energy absorbance efficiency (for photosynthesis). Specifically, photoacclimatory responses were integrated at the morphological and bio-optical levels, with chlorophyll a light harvesting efficiency maintained during reduced pigment density resulting from an increase in host sclerite articulation that maximized the internal light field in healthy clones on degraded reefs. Variable optical responses were not attributed to endosymbiont type, as all test colonies possessed a novel Symbiodinium Clade D1a. In summary, patterns of phenotypic variability within the I. hippuris holobiont likely represent incipient ecological divergence, with a high capacity for plasticity that has become fixed through ongoing anthropogenic disturbance on degraded reefs.