Comparative seascape genetics of co-distributed intertidal snails Monodonta spp. in the Japanese and Ryukyu archipelagoes

2021 ◽  
Vol 657 ◽  
pp. 135-146
Author(s):  
D Yamazaki ◽  
O Miura ◽  
S Uchida ◽  
M Ikeda ◽  
S Chiba
Keyword(s):  
Genetic Variation ◽  
Ecological Factors ◽  
Ecological Studies ◽  
Ecological Traits ◽  
Habitat Specificity ◽  
Closely Related Species ◽  
Powerful Approach ◽  
Intertidal Snail ◽  
Seascape Genetics

Recent molecular ecological studies have focused on how the relationships between physical and ecological factors influence marine biogeography. Comparative phylogeography using closely related species is a powerful approach to evaluate the role of ecological traits in the genetic variation of marine organisms. In the present study, we compared ecological traits and genetic variation in 3 species of the intertidal snail genus Monodonta that co-occur in the Japanese and Ryukyu archipelagoes. We found that M. labio was dominant in sheltered habitats and M. perplexa was dominant in wave-exposed habitats, while M. confusa showed no habitat specificity. This indicates that M. labio and M. perplexa are habitat specialists regarding wave exposure, while M. confusa is a generalist. M. labio and M. perplexa showed lower genetic diversity and greater genetic differentiation among populations than M. confusa. Our findings support the specialist-generalist variation hypothesis in a well-connected marine environment.

scholarly journals The role of APETALA1 in petal number robustness

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Marie Monniaux ◽  
Bjorn Pieper ◽  
Sarah M McKim ◽  
Anne-Lise Routier-Kierzkowska ◽  
Daniel Kierzkowski ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Genetic Variation ◽  
Reproductive Success ◽  
Genetic Basis ◽  
Phenotypic Expression ◽  
Specific Difference ◽  
Closely Related Species ◽  
Epistatic Interactions ◽  
Species Specific

Invariant floral forms are important for reproductive success and robust to natural perturbations. Petal number, for example, is invariant in Arabidopsis thaliana flowers. However, petal number varies in the closely related species Cardamine hirsuta, and the genetic basis for this difference between species is unknown. Here we show that divergence in the pleiotropic floral regulator APETALA1 (AP1) can account for the species-specific difference in petal number robustness. This large effect of AP1 is explained by epistatic interactions: A. thaliana AP1 confers robustness by masking the phenotypic expression of quantitative trait loci controlling petal number in C. hirsuta. We show that C. hirsuta AP1 fails to complement this function of A. thaliana AP1, conferring variable petal number, and that upstream regulatory regions of AP1 contribute to this divergence. Moreover, variable petal number is maintained in C. hirsuta despite sufficient standing genetic variation in natural accessions to produce plants with four-petalled flowers.

scholarly journals Variation in intraspecific demography drives localised concordance but species-wide discordance in responses to Plio-Pleistocene climatic change

2021 ◽  
Author(s):  
Sean James Buckley ◽  
Chris Brauer ◽  
Peter Unmack ◽  
Michael Hammer ◽  
Luciano B Beheregaray
Keyword(s):  
Climate Change ◽  
Genetic Variation ◽  
Demographic History ◽  
Critical Factor ◽  
Future Climate Change ◽  
Peripheral Populations ◽  
Population Declines ◽  
Ecological Traits ◽  
Species Responses

Understanding how species biology may facilitate resilience to climate change remains a critical factor in detecting and protecting species at risk of extinction. Many studies have focused on the role of particular ecological traits in driving species responses, but less so on demographic history and levels of standing genetic variation. We used environmental and genomic datasets to reconstruct the phylogeographic histories of two ecologically similar and largely co-distributed freshwater fishes to assess the degree of concordance in their responses to Plio-Pleistocene climatic changes. Although several co-occurring populations demonstrated concordant demographic histories, idiosyncratic population size changes were found at the range edges of the more spatially restricted species. Discordant responses between species were associated with low standing genetic variation in peripheral populations. This might have hindered adaptive potential, as documented in recent population declines and extinctions of the two species. Our results highlight both the role of spatial scale in the degree of concordance in species responses to climate change, and the importance of standing genetic variation in facilitating range shifts. Even when ecological traits are similar between species, long-term genetic diversity and historical population demography may lead to discordant responses to ongoing and future climate change.

Genetic background of cholesterol absorption efficacy. The role of Niemann–Pick C1-like 1 receptor and its genetic variation in lipid metabolism

2010 ◽  
Vol 151 (34) ◽  
pp. 1376-1383 ◽  
Author(s):  
Mariann Harangi ◽  
István Balogh ◽  
János Harangi ◽  
György Paragh
Keyword(s):  
Genetic Variation ◽  
Lipid Metabolism ◽  
Genetic Background ◽  
Cholesterol Absorption ◽  
Niemann Pick

A Niemann–Pick C1-like-1 egy szterolfelismerő domént tartalmazó membránfehérje, amelyet nagy számban expresszálnak csúcsi felszínükön a bélhámsejtek. Az utóbbi évek vizsgálatai azt igazolták, hogy ez a fehérje szükséges a szabad koleszterin bejutásához a bélhámsejtekbe a bél lumenéből. Biokémiai vizsgálatok azt igazolták, hogy a Niemann–Pick C1-like-1-hez kötődik az ezetimib, amely egy hatékony koleszterinfelszívódást gátló szer. A bélből történő koleszterinfelszívódás ütemében és az ezetimibkezelés hatékonyságában tapasztalt egyéni eltérések hátterében felmerült néhány Niemann–Pick C1-like-1 génvariáció oki szerepe.

scholarly journals Premating barriers in young sympatric snail species

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Arina L. Maltseva ◽  
Marina A. Varfolomeeva ◽  
Arseniy A. Lobov ◽  
Polina O. Tikanova ◽  
Egor A. Repkin ◽  
...  
Keyword(s):  
Gene Flow ◽  
Snail Species ◽  
Sympatric Populations ◽  
Gastropod Species ◽  
Shell Size ◽  
Closely Related Species ◽  
Partial Canonical Correspondence Analysis ◽  
In The Wild ◽  
Isolation Index

AbstractSympatric coexistence of recently diverged species raises the question of barriers restricting the gene flow between them. Reproductive isolation may be implemented at several levels, and the weakening of some, e.g. premating, barriers may require the strengthening of the others, e.g. postcopulatory ones. We analysed mating patterns and shell size of mates in recently diverged closely related species of the subgenus Littorina Neritrema (Littorinidae, Caenogastropoda) in order to assess the role of premating reproductive barriers between them. We compared mating frequencies observed in the wild with those expected based on relative densities using partial canonical correspondence analysis. We introduced the fidelity index (FI) to estimate the relative accuracy of mating with conspecific females and precopulatory isolation index (IPC) to characterize the strength of premating barriers. The species under study, with the exception of L. arcana, clearly demonstrated preferential mating with conspecifics. According to FI and IPC, L. fabalis and L. compressa appeared reliably isolated from their closest relatives within Neritrema. Individuals of these two species tend to be smaller than those of the others, highlighting the importance of shell size changes in gastropod species divergence. L. arcana males were often found in pairs with L. saxatilis females, and no interspecific size differences were revealed in this sibling species pair. We discuss the lack of discriminative mate choice in the sympatric populations of L. arcana and L. saxatilis, and possible additional mechanisms restricting gene flow between them.

Variation in the morphology and flowering time of cluster clover (Trifolium glomeratum L.) and its relationship to distribution in southern Australia

1995 ◽  
Vol 46 (5) ◽  
pp. 1027 ◽  
Author(s):  
FP Smith ◽  
PS Cocks ◽  
MA Ewing
Keyword(s):  
Genetic Variation ◽  
Flowering Time ◽  
Seed Mass ◽  
Annual Rainfall ◽  
Strongly Correlated ◽  
Summer Maximum ◽  
Maximum Temperatures ◽  
Pattern Of Variation ◽  
Growth Habits

Cluster clover is a widely distributed and ecologically successful introduced legume in southern Australia. In an attempt to understand the role of genetic variation in this success, morphological and physiological traits were measured in 94 accessions from southern Australia and 6 from the Mediterranean basin. Flowering time ranged from 105 to 185 days after sowing, but was not strongly correlated with annual rainfall or length of growing season at the site of collection. Variation in other traits partitioned the populations into two morphs which, apart from flowering time and leaf marker, were largely homogeneous. The morphs differed significantly in floret number per inflorescence (22 v. 32-37) and seed mass (379 8g v. 523 8g), had different growth habits and strong within-morph associations between leaf markers and stipule and petal coloration. The morphs differed in their distributions within southern Australia and the pattern of distribution was related to summer maximum temperatures, winter minimum temperatures and spring rainfall. These results demonstrate that genetic variation has been important to the success of cluster clover and suggests that the variation is organized. The pattern of variation observed and its relationship to ecogeography is consistent with findings for other highly inbreeding species. A map of the species distribution in Western Australia is presented.

scholarly journals Molecular Signatures of Reticulate Evolution within the Complex of European Pine Taxa

Forests ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 489
Author(s):  
Bartosz Łabiszak ◽  
Witold Wachowiak
Keyword(s):  
Gene Flow ◽  
Reticulate Evolution ◽  
Modeling Framework ◽  
Closely Related Species ◽  
Interspecific Gene Flow ◽  
Nucleotide Sequence Variation ◽  
History Of ◽  
Best Fitting ◽  
Species Integrity

Speciation mechanisms, including the role of interspecific gene flow and introgression in the emergence of new species, are the major focus of evolutionary studies. Inference of taxonomic relationship between closely related species may be challenged by past hybridization events, but at the same time, it may provide new knowledge about mechanisms responsible for the maintenance of species integrity despite interspecific gene flow. Here, using nucleotide sequence variation and utilizing a coalescent modeling framework, we tested the role of hybridization and introgression in the evolutionary history of closely related pine taxa from the Pinus mugo complex and P. sylvestris. We compared the patterns of polymorphism and divergence between taxa and found a great overlap of neutral variation within the P. mugo complex. Our phylogeny reconstruction indicated multiple instances of reticulation events in the past, suggesting an important role of interspecific gene flow in the species divergence. The best-fitting model revealed P. mugo and P. uncinata as sister species with basal P. uliginosa and asymmetric migration between all investigated species after their divergence. The magnitude of interspecies gene flow differed greatly, and it was consistently stronger from representatives of P. mugo complex to P. sylvestris than in the opposite direction. The results indicate the prominent role of reticulation evolution in those forest trees and provide a genetic framework to study species integrity maintained by selection and local adaptation.

scholarly journals Group size and aquatic vegetation modulates male preferences for female shoals in wild zebrafish, Danio rerio

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Aditya Ghoshal ◽  
Anuradha Bhat
Keyword(s):  
Group Size ◽  
Aquatic Vegetation ◽  
Natural Habitat ◽  
Ecological Factors ◽  
Choice Test ◽  
Female Group ◽  
Aquatic Flora ◽  
In The Wild ◽  
The Individual

AbstractShoaling decisions in the wild are determined by a combination of innate preferences of the individual along with the interplay of multiple ecological factors. In their natural habitat as well as in the laboratory, zebrafish is a shoaling fish. Here, we investigate the role of group size and associated vegetation in shaping shoaling preferences of wild male zebrafish. We studied the association preference of males to groups of female shoals in a multi-choice test design. We found that males made greater proportion of visits to an 8-female group compared to 2 and 4-female groups. However, males spent similar proportions of time across the three female-containing groups. When artificial vegetation was incorporated along with female number as an additional factor, we found that males prefer high and moderately vegetated patches compared to low or no-vegetation groups, irrespective of the number of females in these patches. Based on experiments using a novel multi-choice design, our results show that preference for group size can change due to interaction of two separate factors. This work is a first attempt to understand the role of aquatic flora in determining shoaling preferences in zebrafish, using an experimental paradigm consisting of a gradation in female and vegetation densities.

scholarly journals Cryptic variation and its manifestation in the Lower Trentonian Rafinesquina lineage (Ordovician, New York State)

1992 ◽  
Vol 6 ◽  
pp. 292-292
Author(s):  
Robert Titus
Keyword(s):  
New York ◽  
Genetic Variation ◽  
Natural Selection ◽  
New York State ◽  
Ecological Factors ◽  
Stabilizing Selection ◽  
Rapid Population Growth ◽  
York State ◽  
Cryptic Variation ◽  
Adaptive Peak

Species populations commonly carry a great deal of genetic variation which is not expressed in individual phenotypes. Cryptic variation can be carried in recessive alleles, in cases of heterosis, or where modifier genes inhibit expression of the hidden trait. Other genetic and ecological factors also allow cryptic variation. Stabilizing selection prevents the expression of hidden traits; normalizing selection weeds out the deviants and canalizing selection suppresses their traits. Together the two keep the species near the top of the adaptive peak. Cryptic variation balances a species' need to be well-adapted to its environment and also for it to maintain a reserve of variation for potential environmental change. Expression of cryptic traits is rare and is usually associated with times of greatly reduced natural selection and rapid population growth, when the lower slopes of the adaptive peak are exposed.A possible example of the manifestation of cryptic traits occurs within the lower Trentonian Rafinesquina lineage of New York State. The two most commonly reported species of the genus have been reappraised in terms of cryptic variation. Extensive collections of Rafinesquina “lennoxensis” reveal far more intergrading morphotypes than had hitherto been recognized. The form which Salmon (1942) described is broadly U-shaped with sulcate margins. It grades into very convex forms as well as sharply-defined or convexly geniculate types. Of great importance, all forms grade into the flat, U-shaped, alate R. trentonensis, which is, by far, the most common and widespread lower Trentonian member of the genus. The R. “lennoxensis” assemblage has a very narrow biostratigraphy, being confined to a few locations in the upper Napanee Limestone. This places it in a quiet, protected, low stress, lagoonal setting behind the barrier shoal facies of the Kings Falls Limestone.The R. “lennoxensis” assemblage does not constitute a natural biologic species; it is reinterpreted as an assemblage of phenodeviants occupying a low stress, low natural selection lagoon facies. All such forms should be included within R. trentonensis. Given the evolutionary plasticity of this genus, extensive cryptic variation is not surprising.

Ecological Studies on Aphides infesting the Potato Crop

1932 ◽  
Vol 23 (4) ◽  
pp. 535-548 ◽  
Author(s):  
W. Maldwyn Davies
Keyword(s):  
Myzus Persicae ◽  
Potato Crop ◽  
Ecological Studies ◽  
Predominant Species ◽  
Autumn And Winter ◽  
Initial Infestation

1. Ecological studies on aphides attacking potatoes were commenced in 1928 with a view to elucidating certain problems of entomological interest and also the role of these insects as vectors of disease. The species include, Myzus persicae, Sulz., Macrosiphum gei, Koch, and Myzus pseudosolani, Theo.2. The present study is confined mainly to the infestation of aphides on potatoes at a selected centre which is described.3. Solitary apterous viviparous females were in a majority on potatoes during the period of initial infestation in early June. Their presence is explained by (1) the overwintering of aphides on weeds and field plants, (2) the first few alatae depositing single nymphs and then migrating, (3) infection from infested seed.4. The maximum infestation was reached during mid-July, when 86 per cent. of the leaves were infested and there was an average of 2·8 aphides to a leaf. The infestation was below that of the previous three years. Macrosiphum gei bred up rapidly, at first on the flower-heads, and was the predominant species, its decline in numbers being equally rapid. Myzus persicae increased more slowly and did not reach such numbers, but the maximum was maintained longer and the disappearance of the species was delayed. Myzus pseudosolani was only taken in August and then in small numbers.5. An estimate of the intensity of the aphis population is attempted, and in the present moderate infestation of 2·8 aphides to a leaf it was of the order of 2,000,000 aphides to an acre of potatoes.6. A technique was established to ascertain the movement of aphides within the crop. Weekly records on observational leaves revealed that 100 per cent. of the aphides moved their site and at least 84 per cent. of each species moved from leaf to leaf within the weekly period. Daily records during the period of maximum infestation showed that 84 per cent. of Macrosiphum gei and 73 per cent. of Myzus persicae changed site within 24 hours, and of these at least 50 per cent. moved from the leaves upon which they had been observed.7. It was noted that no attempt was made to maintain large local colonies, for the movement of both adults and nymphs was frequent, and observed colonies soon dispersed. The extended infestation of Myzus persicae is discussed with reference to its establishment on field plants, other than potatoes, during the autumn and winter.

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