scholarly journals Independent evolution towards larger body size in the distinctive Faroe Island mice

2021 ◽  
Author(s):  
Ricardo Wilches ◽  
William H Beluch ◽  
Ellen McConnell ◽  
Diethard Tautz ◽  
Yingguang Frank Chan
Keyword(s):  
Body Size ◽  
Meta Analysis ◽  
Small Body ◽  
Laboratory Mouse ◽  
Large Body ◽  
Natural Populations ◽  
Size Variation ◽  
Phenotypic Traits ◽  
Island Population ◽  
Multiple Loci

Abstract Most phenotypic traits in nature involve the collective action of many genes. Traits that evolve repeatedly are particularly useful for understanding how selection may act on changing trait values. In mice, large body size has evolved repeatedly on islands and under artificial selection in the laboratory. Identifying the loci and genes involved in this process may shed light on the evolution of complex, polygenic traits. Here, we have mapped the genetic basis of body size variation by making a genetic cross between mice from the Faroe Islands, which are among the largest and most distinctive natural populations of mice in the world, and a laboratory mouse strain selected for small body size, SM/J. Using this F2 intercross of 841 animals, we have identified 111 loci controlling various aspects of body size, weight and growth hormone levels. By comparing against other studies, including the use of a joint meta-analysis, we found that the loci involved in the evolution of large size in the Faroese mice were largely independent from those of a different island population or other laboratory strains. We hypothesize that colonization bottleneck, historical hybridization, or the redundancy between multiple loci have resulted in the Faroese mice achieving an outwardly similar phenotype through a distinct evolutionary path.

scholarly journals Independent evolution towards large body size in the distinctive Faroe Island mice

2019 ◽  
Author(s):  
Ricardo Wilches ◽  
William H. Beluch ◽  
Ellen McConnell ◽  
Diethard Tautz ◽  
Yingguang Frank Chan
Keyword(s):  
Body Size ◽  
Meta Analysis ◽  
Small Body ◽  
Laboratory Mouse ◽  
Large Body ◽  
Size Variation ◽  
Island Population ◽  
Large Body Size ◽  
Multiple Loci ◽  
Similar Phenotype

AbstractMost traits in nature involve the collective action of many genes. Traits that evolve repeatedly are particularly revealing about how selection may act on traits. In mice, large body size has evolved repeatedly on islands and under artificial selection in the laboratory. Identifying the loci and genes involved in this process may shed light on the evolution of complex, polygenic traits. Here, we have mapped the genetic basis of body size variation by making a genetic cross between mice from the Faroe Islands, which are among the largest and most distinctive populations of mice in the world, and a laboratory mouse strain selected for small body size, SM/J. Using this F2 intercross of 841 animals, we have identified 102 loci controlling various aspects of body size, weight and growth hormone levels. By comparing against other studies, including the use of a joint meta-analysis, we found that the loci involved in the evolution of large size in the Faroese mice were largely independent from those of a different island population or other laboratory strains. We conclude that colonization bottleneck, historical hybridization, or the redundancy between multiple loci have resulted in the Faroese mice achieving an outwardly similar phenotype through a distinct evolutionary path.

scholarly journals Genetic testing of dogs predicts problem behaviors in clinical and nonclinical samples

2020 ◽  
Author(s):  
Isain Zapata ◽  
M. Leanne Lilly ◽  
Meghan E. Herron ◽  
James A. Serpell ◽  
Carlos E. Alvarez
Keyword(s):  
Body Size ◽  
Problem Behaviors ◽  
Small Body ◽  
Community Sample ◽  
Large Body ◽  
Second Phase ◽  
Logistic Regression Models ◽  
Individual Level ◽  
Increased Risk ◽  
Phenotype Data

AbstractVery little is known about the etiology of personality and psychiatric disorders. Because the core neurobiology of many such traits is evolutionarily conserved, dogs present a powerful model. We previously reported genome scans of breed averages of ten traits related to fear, anxiety, aggression and social behavior in multiple cohorts of pedigree dogs. As a second phase of that discovery, here we tested the ability of markers at 13 of those loci to predict canine behavior in a community sample of 397 pedigree and mixed-breed dogs with individual-level genotype and phenotype data. We found support for all markers and loci. By including 122 dogs with veterinary behavioral diagnoses in our cohort, we were able to identify eight loci associated with those diagnoses. Logistic regression models showed subsets of those loci could predict behavioral diagnoses. We corroborated our previous findings that small body size is associated with many problem behaviors and large body size is associated with increased trainability. Children in the home were associated with anxiety traits; illness and other animals in the home with coprophagia; working-dog status with increased energy and separation-related problems; and competitive dogs with increased aggression directed at familiar dogs, but reduced fear directed at humans and unfamiliar dogs. Compared to other dogs, Pit Bull-type dogs were not defined by a set of our markers and were not more aggressive; but they were strongly associated with pulling on the leash. Using severity-threshold models, Pit Bull-type dogs showed reduced risk of owner-directed aggression (75th quantile) and increased risk of dog-directed fear (95th quantile). Our findings have broad utility, including for clinical and breeding purposes, but we caution that thorough understanding is necessary for their interpretation and use.

Alternative Reproductive Tactics

2020 ◽  
pp. 429-446
Author(s):  
Shawn Garner ◽  
Bryan Neff
Keyword(s):  
Body Size ◽  
Small Body ◽  
Large Body ◽  
Morphological Differentiation ◽  
Alternative Reproductive Tactics ◽  
Reproductive Tactics ◽  
Aggressive Interactions ◽  
Single Sex ◽  
Female Mimicry ◽  
Mating Opportunities

Alternative reproductive tactics (ARTs) describe variation among individuals of a single sex in the tactics used to obtain mating opportunities. In crustaceans, ARTs have been observed in multiple taxa and take a variety of forms. ARTs are most commonly observed in males and are generally associated with intense competition among males to monopolize access to breeding females. ARTs frequently involve a guard tactic that competes with other males to monopolize access to females, while a second usurper tactic foregos competition with other males and instead obtains mating opportunities through sneaking behavior. Guard and usurper tactics may be expressed conditionally based on a male’s ability to guard a female (e.g. his body size, the abundance of competitors), or may be expressed as discrete phenotypes that can also include morphological differentiation. For example, in Jassa amphipods the guard tactic is associated with large body size and an enlarged “thumb” on the claw that is used in aggressive interactions with other males, while the usurper tactic is associated with small body size and a reduced thumb. The usurper tactic can take two forms in a marine isopod: small males (gamma) use sneaking behavior to avoid competition with large males (alpha), whereas intermediate-sized males (beta) use female mimicry to avoid competition. Overall, ARTs are well-represented in crustaceans, with many opportunities for continued study to better characterize these unique adaptations.

scholarly journals Altered trait variability in response to size-selective mortality

2016 ◽  
Vol 12 (9) ◽  
pp. 20160584 ◽  
Author(s):  
Silva Uusi-Heikkilä ◽  
Kai Lindström ◽  
Noora Parre ◽  
Robert Arlinghaus ◽  
Josep Alós ◽  
...  
Keyword(s):  
Body Size ◽  
Phenotypic Variability ◽  
Large Body ◽  
Size Variation ◽  
Directional Selection ◽  
Fish Stocks ◽  
Alternative Feeding ◽  
Stability And Resilience ◽  
Feeding Environments ◽  
Trait Variability

Changes in trait variability owing to size-selective harvesting have received little attention in comparison with changes in mean trait values, perhaps because of the expectation that phenotypic variability should generally be eroded by directional selection typical for fishing and hunting. We show, however, that directional selection, in particular for large body size, leads to increased body-size variation in experimentally harvested zebrafish ( Danio rerio ) populations exposed to two alternative feeding environments: ad libitum and temporarily restricted food availability. Trait variation may influence population adaptivity, stability and resilience. Therefore, rather than exerting selection pressures that favour small individuals, our results stress the importance of protecting large ones, as they can harbour a great amount of variation within a population, to manage fish stocks sustainably.

Description of two new species from Venezuela in the highly diverse dipsadine genus Atractus (Serpentes: Colubridae)

2009 ◽  
Vol 30 (2) ◽  
pp. 233-243 ◽  
Author(s):  
Gilson Rivas Fuenmayor ◽  
Paulo Passos ◽  
Cesar Barrio-Amorós
Keyword(s):  
New Species ◽  
Body Size ◽  
Small Body ◽  
Large Body ◽  
Species Description ◽  
Small Body Size ◽  
Single Female ◽  
Large Body Size ◽  
Body Diameter ◽  
Two New Species

AbstractTwo new species of Atractus are described from Venezuela uplands and highlands on two northern Andean cordilleras. Atractus acheronius, known only from Sierra de Perijá, can be distinguished from congeners by having 17 dorsal scale rows, presence of preocular scales, seven upper and lower labials, seven maxillary teeth, 166 ventrals in the single female, 23 subcaudals, dorsum brown with small dark brown dots, large body size, huge body diameter, and small tail size. Atractus multidentatus, known only from north versant of the Cordillera de Mérida, can be distinguished from congeners by having 17 dorsal scale rows, eight upper and lower labials, 18 maxillary teeth, 153 ventrals in the single female, nine subcaudals, dorsum reddish brown with five longitudinal dark brown stripes, small body size, small body diameter, and small tail size. Additionally, a discussion concerning the species description of Atractus based on unique specimens is provided.

scholarly journals Ocean acidification and bivalve byssus: explaining variable responses using meta-analysis

2021 ◽  
Author(s):  
Jeff Clements ◽  
Matthew N. George
Keyword(s):  
Body Size ◽  
Ocean Acidification ◽  
Effect Size ◽  
Literature Search ◽  
Meta Analysis ◽  
Size Variation ◽  
Future Research ◽  
Systematic Literature Search ◽  
Attachment Strength ◽  
The Impact

1. Many bivalve molluscs settle and attach to surfaces using adhesive byssal threads – proteinaceous fibers that together form a network known as the byssus. Since these bivalves rely on byssus for survival, strong byssal attachment promotes a myriad of broad ecological services, including water filtration, nutrient extraction, sediment stabilization, and enhancing biodiversity through habitat creation.2. Numerous studies have documented weakened byssal attachment strength under ocean acidification (OA); however, a comparable number report no effect, even within the same species. Consequently, whether elevated CO2 levels expected under near-future OA will affect byssal attachment strength in nature remains hotly contested.3. We used a systematic literature search and meta-analysis to explore factors that could potentially explain observed effect size variation in byssal attachment strength following OA exposure. 4. A systematic literature search uncovered 20 studies experimentally testing the impact of OA on byssal attachment strength (or some proxy thereof). Meta-analysis revealed that body size (mean shell length) was the strongest predictor of effect size variation, with no significant effect of climate, species, year, study temperature, study location, exposure time, food amount, and pH offset. Functionally, a negative linear relationship was observed between body size and effect size.5. Our finding that the byssal strength of larger bivalves is more susceptible to negative OA effects runs counter to prevailing wisdom that larger, older animals of a given species are more robust to OA than earlier life history stages. 6. This highlights that body size and age may be important factors that determine OA sensitivity in adult calcifiers. In addition to body size, a critical review of each study revealed commonly neglected factors that could influence byssal thread attachment strength which we highlight to provide suggestions for future research in this area.

scholarly journals Big City Living: A Global Meta-Analysis Reveals Positive Impact of Urbanization on Body Size in Lizards

2020 ◽  
Vol 8 ◽  
Author(s):  
Breanna J. Putman ◽  
Zachary A. Tippie
Keyword(s):  
Body Size ◽  
Positive Impact ◽  
Meta Analysis ◽  
Urban Environments ◽  
Phenotypic Traits ◽  
Ecological Communities ◽  
Qualitative Synthesis ◽  
Big City ◽  
Impact Of Urbanization ◽  
Taxonomic Groups

Urban environments pose different selective pressures than natural ones, leading to changes in animal behavior, physiology, and morphology. Understanding how animals respond to urbanization could inform the management of urban habitats. Non-avian reptiles have important roles in ecosystems worldwide, yet their responses to urbanization have not been as comprehensively studied as those of mammals and birds. However, unlike mammals and birds, most reptiles cannot easily move away from disturbances, making the selective pressure to adapt to urban environments especially strong. In recent years, there has been a surge in research on the responses of lizards to urbanization, yet no formal synthesis has determined what makes an urban lizard, in other words, which phenotypic traits are most likely to change with urbanization and in which direction? Here, we present a qualitative synthesis of the literature and a quantitative phylogenetic meta-analysis comparing phenotypic traits between urban and non-urban lizard populations. The most robust finding from our analysis is that urban lizards are larger than their non-urban counterparts. This result remained consistent between sexes and taxonomic groups. Hence, lizards that pass through the urban filter have access to better resources, more time for foraging, and/or there is selection on attaining a larger body size. Other results included an increase in the diameters of perches used and longer limb and digit lengths, although this may be a result of increased body size. Urban lizards were not bolder, more active or exploratory, and did not differ in immune responses than non-urban populations. Overall, studies are biased to a few geographic regions and taxa. More than 70% of all data came from three species of anoles in the family Dactyloidae, making it difficult to generalize patterns to other clades. Thus, more studies are needed across multiple taxa and habitats to produce meaningful predictions that could help inform conservation and management of urban ecological communities.

Prey preference of a wasp determined by nest size supports the role of natural selection in body size evolution in Cassidinae leaf beetles

2021 ◽  
Author(s):  
Tadashi Shinohara ◽  
Yasuoki Takami
Keyword(s):  
Body Size ◽  
Natural Selection ◽  
Prey Species ◽  
Large Body ◽  
Size Variation ◽  
Prey Preference ◽  
Nest Size ◽  
Large Prey ◽  
Leaf Beetles ◽  
Body Sizes

Abstract The prey preference of a predator can impose natural selection on prey phenotypes, including body size. Despite evidence that large body size protects against predation in insects, the determinants of body size variation in Cassidinae leaf beetles are not well understood. We examined the prey preference of the digger wasp Cerceris albofasciata, a specialist predator of adult Cassidinae leaf beetles, and found evidence for natural selection on prey body size. The wasp hunted prey smaller than the size of their nest entrance. However, the wasp preferred larger prey species among those that could be carried into their nest. Thus, the benefits of large prey and the cost associated with nest expansion might determine the prey size preference. As expected from the prey species preference, the wasp preferred small individuals of the largest prey species, Thlaspida biramosa, and large individuals of the smallest prey species, Cassida piperata, resulting in natural selection on body sizes. In intermediate-sized prey species, however, there was no evidence for selection on body size. Natural selection on body size might explain the variation of prey morphologies that increase body size, such as explanate margins, in this group.

A new species of Sitana (Squamata: Agamidae) from the Deccan Peninsula Biogeographic Zone of India

Zootaxa ◽  
2021 ◽  
Vol 4948 (2) ◽  
pp. 261-274
Author(s):  
V. DEEPAK ◽  
FRANK TILLACK ◽  
NILADRI B. KAR ◽  
VIVEK SARKAR ◽  
PRATYUSH. P. MOHAPATRA
Keyword(s):  
New Species ◽  
Body Size ◽  
Small Body ◽  
Large Body ◽  
Morphological Characters ◽  
Adult Males ◽  
Blue Line ◽  
Dark Blue ◽  
A New Species ◽  
Bright Blue

We describe a new species of fan-throated lizard of the genus Sitana from the Deccan peninsula of India. The new species is from the Sitana sivalensis clade and can be readily diagnosed morphologically from S. sivalensis, S. fusca and S. schleichi by having the dewlap extending beyond forearm insertion. The new species differs from all other congeners in the combination of morphological characters such as a feebly serrated dewlap with a dark blue line on the throat in adult males (versus  a well serrated dewlap with a bright blue patch and orange spots in S. ponticeriana complex), small body size (versus a large body size in S. gokakensis and S. thondalu) and a relatively smaller dewlap size (relatively larger in S. laticeps, S. spinaecephalus, S. dharwarensis, S. gokakensis, S. thondalu, S. marudhamneydhal, S. ponticeriana and S. visiri). The new species was found to be commonly distributed in arid and open habitats as well as in farmlands and plantations in northern Andhra Pradesh, eastern Madhya Pradesh and most parts of Chhattisgarh and Odisha states. 

PATTERNS IN MAYFLY (EPHEMEROPTERA) WING LENGTH: ADAPTATION TO DISPERSAL?

1987 ◽  
Vol 119 (9) ◽  
pp. 783-790 ◽  
Author(s):  
Lynda D. Corkum
Keyword(s):  
Regression Analysis ◽  
Body Size ◽  
Body Length ◽  
Wing Length ◽  
Small Body ◽  
Large Body ◽  
Habitat Type ◽  
Allometric Relationships ◽  
Small Lake ◽  
Rivers And Lakes

AbstractUsing regression analysis on data compiled from the literature, I compared relationships (forewing versus body length) of mayfly imagoes, as a measure of dispersal, between suborders (Schistonota and Pannota) and among habitat type (lotic, lentic, and mixed). There were no significant differences in slopes or intercepts of the regression lines between sexes. Forewing length changed less markedly with body size for species within the ancestral Schistonota than the Pannota. Regression lines for lake and river forms intersect at 7.85 mm (wing length) and 7.30 mm (body length). Small (body length < 7.3 mm) lentic mayflies have proportionately longer wings than small riverine forms. Large (body length > 7.3 mm) riverine mayflies have proportionately longer wings than lentic forms. Based on these relationships, small lake-dwelling mayflies and large riverine mayflies are best able to disperse. Mayfly species occurring in mixed (both rivers and lakes) habitats exhibited allometric relationships similar to mayflies restricted to rivers.

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