Individual differences: Variation by design

2000 ◽  
Vol 23 (5) ◽  
pp. 676-677 ◽  
Author(s):  
Anthony J. Greene ◽  
William B. Levy

Stanovich & West (S&W) appear to overlook the adaptivity of variation. Behavioral variability, both between and within individuals, is an absolute necessity for phylogenetic and ontological adaptation. As with all heritable characteristics, inter-individual behavioral variation is the foundation for natural selection. Similarly, intra-individual variation allows a broad exploration of potential solutions. Variation increases the likelihood that more optimal behaviors are available for selection. Four examples of the adaptivity of variation are discussed: (a) Genetic variation as it pertains to behavior and natural selection; (b) behavioral and cognitive aspects of mate selection which may facilitate genetic diversity; (c) variation as a strategy for optimizing learning through greater exploration; and (d) behavioral variation coupled with communication as a means to propagate individually discovered behavioral success.

2016 ◽  
Author(s):  
Kevin D Matson ◽  
Maaike A Versteegh ◽  
B Irene Tieleman

Animals exhibit seasonal cycles in a variety of physiological and behavioral traits. Studies of these cycles can potentially offer new insights into the evolution of individual differences. For natural selection to act, a trait must be both distinctive within individuals and variable among individuals. The extent to which the amplitude and phase of seasonal cycles fulfill these requirements is not well documented. As a preliminary analysis, we investigated seasonal cycles in the body mass of pigeons, which we weighed quarterly over a period of six years. [Our work with these animals complied with all applicable institutional regulations (University of Groningen Animal Experimentation Committee, license no. 5095) and Dutch and European laws.] We employed several of statistical techniques aimed at 1) quantifying the repeatability of seasonality and 2) comparing within- and among-individual variation in seasonality. Our goal is to take what we have learned from our analyses of mass and apply it to other seasonally variable physiological traits, including variables related to immune function.


2018 ◽  
Author(s):  
Daniel Koenig ◽  
Jörg Hagmann ◽  
Rachel Li ◽  
Felix Bemm ◽  
Tanja Slotte ◽  
...  

ABSTRACTGenetic drift is expected to remove polymorphism from populations over long periods of time, with the rate of polymorphism loss being accelerated when species experience strong reductions in population size. Adaptive forces that maintain genetic variation in populations, or balancing selection, might counteract this process. To understand the extent to which natural selection can drive the retention of genetic diversity, we document genomic variability after two parallel species-wide bottlenecks in the genus Capsella. We find that ancestral variation preferentially persists at immunity related loci, and that the same collection of alleles has been maintained in different lineages that have been separated for several million years. Our data point to long term balancing selection as an important factor shaping the genetics of immune systems in plants and as the predominant driver of genomic variability after a population bottleneck.


2012 ◽  
Vol 58 (4) ◽  
pp. 580-588 ◽  
Author(s):  
Noa Pinter-Wollman

Abstract Social insect colonies and the workers comprising them, each exhibit consistent individual differences in behavior, also known as ‘personalities’. Because the behavior of social insect colonies emerges from the actions of their workers, individual variation among workers’ personality may be important in determining the variation we observe among colonies. The reproductive unit of social insects, on which natural selection acts, is the colony, not individual workers. Therefore, it is important to understand what mechanisms govern the observed variation among colonies. Here I propose three hypotheses that address how consistent individual differences in the behavior of workers may lead to consistent individual differences in the behavior of colonies: 1. Colonies differ consistently in their average of worker personality; 2. The distribution but not the average of worker personalities varies consistently among colonies; and 3. Colony personality does not emerge from its worker personality composition but from consistent external constraints. I review evidence supporting each of these hypotheses and suggest methods to further investigate them. The study of how colony personality emerges from the personalities of the workers comprising them may shed light on the mechanisms underlying consistent individual differences in the behavior of other animals.


2016 ◽  
Author(s):  
Kevin D Matson ◽  
Maaike A Versteegh ◽  
B Irene Tieleman

Animals exhibit seasonal cycles in a variety of physiological and behavioral traits. Studies of these cycles can potentially offer new insights into the evolution of individual differences. For natural selection to act, a trait must be both distinctive within individuals and variable among individuals. The extent to which the amplitude and phase of seasonal cycles fulfill these requirements is not well documented. As a preliminary analysis, we investigated seasonal cycles in the body mass of pigeons, which we weighed quarterly over a period of six years. [Our work with these animals complied with all applicable institutional regulations (University of Groningen Animal Experimentation Committee, license no. 5095) and Dutch and European laws.] We employed several of statistical techniques aimed at 1) quantifying the repeatability of seasonality and 2) comparing within- and among-individual variation in seasonality. Our goal is to take what we have learned from our analyses of mass and apply it to other seasonally variable physiological traits, including variables related to immune function.


2018 ◽  
Vol 41 ◽  
Author(s):  
Benjamin C. Ruisch ◽  
Rajen A. Anderson ◽  
David A. Pizarro

AbstractWe argue that existing data on folk-economic beliefs (FEBs) present challenges to Boyer & Petersen's model. Specifically, the widespread individual variation in endorsement of FEBs casts doubt on the claim that humans are evolutionarily predisposed towards particular economic beliefs. Additionally, the authors' model cannot account for the systematic covariance between certain FEBs, such as those observed in distinct political ideologies.


2019 ◽  
Vol 42 ◽  
Author(s):  
Emily F. Wissel ◽  
Leigh K. Smith

Abstract The target article suggests inter-individual variability is a weakness of microbiota-gut-brain (MGB) research, but we discuss why it is actually a strength. We comment on how accounting for individual differences can help researchers systematically understand the observed variance in microbiota composition, interpret null findings, and potentially improve the efficacy of therapeutic treatments in future clinical microbiome research.


HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 534e-534 ◽  
Author(s):  
J. Staub ◽  
Felix Sequen ◽  
Tom Horejsi ◽  
Jin Feng Chen

Genetic variation in cucumber accessions from China was assessed by examining variation at 21 polymorphic isozyme loci. Principal component analysis of allelic variation allowed for the depiction of two distinct groupings of Chinese accessions collected in 1994 and 1996 (67 accessions). Six isozyme loci (Gpi, Gr, Mdh-2, Mpi-2, Pep-gl, and Pep-la) were important in elucidating these major groups. These groupings were different from a single grouping of Chinese 146 accessions acquired before 1994. Allelic variation in Chinese accessions allowed for comparisons with other accessions in the U.S. National Plant Germplasm System (U.S. NPGS) collection grouped by continent and sub-continent. When Chinese accessions taken collectively were compared with an array of 853 C. sativus U.S. NPGS accessions examined previously, relationships differed between accessions grouped by country or subcontinent. Data indicate that acquisition of additional Chinese and Indian cucumber accessions would be strategically important for increasing genetic diversity in the U.S. NPGS cucumber collection.


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